Rescuers search for survivors at a collapsed building in Mamuju city on January 15, 2021, after a 6.2-magnitude earthquake rocked Indonesia's Sulawesi island. Firdaus / AFP / Getty Images
At least 42 people are confirmed dead and more than 600 injured after a 6.2 magnitude earthquake struck the Indonesian island of Sulawesi early Friday morning.
<p>The earthquake and subsequent aftershocks also damaged more than 300 homes and two hotels, and destroyed a hospital and the regional governor's office, leaving people trapped under rubble and forcing around 15,000 to flee their homes, <a href="https://www.reuters.com/article/us-indonesia-quake/indonesia-quake-kills-at-least-35-injures-hundreds-idUSKBN29K00X" target="_blank">Reuters reported</a>. The global pandemic complicates matters, likely making it harder to provide aid.</p><p>"[T]his (disaster) was one of our fears and now we are putting all of that planning and protocols into place," Jan Gelfand, head of the International Federation of Red Cross in Indonesia, told Reuters.</p><p>The earthquake struck at 1:28 a.m. Jakarta time at a depth of 6.2 miles, Indonesia's Meteorology, Climatology and Geophysics Agency said, according to <a href="https://www.cnn.com/2021/01/14/asia/indonesia-sulawesi-earthquake-intl-hnk/index.html" target="_blank">CNN</a>. The quake hit 3.7 miles northeast of the city of Majene, killing at least eight people, injuring 637 and damaging 300 homes. It also impacted the nearby area of Mamuju, where the death toll has reached 34 so far. Nearly half of the structures there have also been destroyed, Safaruddin Sanusi, the head of West Sulawesi's Communications and Information Department, told CNN.</p><p>Sanusi said rescue workers' priority involved finding people in collapsed buildings. Unfortunately, the death toll will likely rise as this work continues.</p>
<p>"I'm afraid to say how many fatalities," Ardiansyah, a West Sulawesi emergency response official, told <a href="https://www.nytimes.com/2021/01/15/world/asia/indonesia-earthquake-sulawesi.html?auth=login-google" target="_blank">The New York Times</a>. "We are still evacuating and erecting shelters. Many people are buried under the ruins."</p><p>Among the collapsed or damaged buildings were four of Mamuju's largest hospitals, Sanusi told CNN.</p><p>"Mitra Manakara [Hospital] is flattened by this earthquake, while three others, Mamuju Central Hospital, Bhayangkara Hospital and Regional Hospital are also in [a] bad situation," he said.</p><p>At Mitra Manakara Hospital, eight people died and around 60 were safely evacuated, <a href="https://www.bbc.com/news/world-asia-55672126" target="_blank">BBC News reported</a>.</p><p>"It happened so quickly, around 10 seconds," local police spokesman Syamsu Ridwan told the BBC.</p>
<p>The earthquake also triggered three landslides, cut power and damaged bridges, Reuters reported.</p><p>Indonesia is located on the Pacific Ring of Fire, a hotbed for seismic activity. In 2018, a 7.5 earthquake and 18-foot <a href="https://www.ecowatch.com/tag/tsunami" target="_self">tsunami</a> also <a href="https://www.ecowatch.com/indonesia-earthquake-tsunami-2610020141.html" target="_blank">devastated the island of Sulawesi</a>. The final death toll surpassed 2,000, according to BBC News. Friday's earthquake did not trigger a tsunami, but officials warned that aftershocks still could.</p><p>There were six tremors of 2.9 magnitude or higher in the 12 hours before the major earthquake struck, The New York Times reported. It was then followed by at least 26 aftershocks, Dwikorita Karnawati, the head of Indonesia's Meteorology and Geophysics Agency, told Reuters. The aftershocks have caused persistent anxiety for survivors.</p><p>"Praise be to God, for now OK, but we just felt another aftershock," area resident Sukri Efendy told Reuters.</p>
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Gas and steam erupt from the Halemaumau Crater of the Kilauea Volcano on December 21, 2020 in Hawaii Volcanoes National Park, Hawaii. Andrew Richard Hara / Getty Images
Kilauea, a large volcano on the Island of Hawai'i (or Big Island) and one of the most active in the world, erupted Sunday night following a series of earthquakes, CNN reported.
<p>The eruption sent lava shooting into the air, along with a huge cloud of ash and steam. Hawaiian officials urged residents to stay indoors shortly after the eruption.</p><p><span></span>"Trade winds will push any embedded ash toward the Southwest. Fallout is likely in the Kau District in Wood Valley, Pahala, Naalehu and Ocean View. Stay indoors," an official from Civil Defense Agency tweeted, according to CNN.</p><p>However, the lava posed little risk to residents due to the eruption's location on Halemaumau within Hawaii Volcanoes National Park, the<a href="https://apnews.com/article/hawaii-volcano-kilauea-big-island-erupts-506654609db9ec7041e6054c877df092" target="_blank"> AP reported.</a></p>
<p>The <a href="https://www.usgs.gov/observatories/hawaiian-volcano-observatory" target="_blank" rel="noopener noreferrer">Hawaiian Volcano Observatory</a>, (HVO) which monitors activity at Kilauea and its sister volcano Mauna Kea, issued a red <a href="https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels" target="_blank" rel="noopener noreferrer">aviation code</a> alert after the initial eruption, but has since lowered it to an orange alert, meaning another significant eruption may still be possible.</p><p>The <a href="https://www.usgs.gov/news/k-lauea-volcano-erupts-0" target="_blank">U.S. Geological Survey</a> (USGS) also reported a 4.4 magnitude earthquake that struck about an hour after the initial eruption. The USGS received more than 500 reports from people who felt the earthquake, but no major damage has been reported, according to the AP.</p><p><span></span>Kilauea last erupted in May 2018. That event involved a period of earthquakes and eruptions lasting for four months, creating lava flows that destroyed <a href="https://www.ecowatch.com/volcano-in-hawaii-kilauea-2576341256.html" target="_blank">more than 700 homes</a>, the AP reported.</p>
<p>The 2018 activity also caused Halemaumau's longtime lava lake to drain, according to the AP. In 2019, a new <a href="https://www.ecowatch.com/water-in-hawaiis-kilauea-volcano-2639727399.html?rebelltitem=1#rebelltitem1" target="_blank">body of water</a> was discovered in Kilauea's crater, leading to speculation about future eruptions, the New York Times found.</p><p>Jessica Ferracane, a Hawaii Volcanoes National Park spokeswoman, told the AP that curious park spectators should take precautions. "There are high amounts of hazardous sulfur dioxide gas and particulates and those are billowing out of the crater right now and those present a danger to everyone, especially people with heart or respiratory problems, infants, young children and pregnant women."</p><p>Despite <a href="https://volcano.si.edu/faq/index.cfm?question=eruptionsbyyear&checkyear=2020" target="_blank">67 confirmed eruptions</a> around the world in 2020, experts at the Smithsonian's <a href="https://volcano.si.edu/faq/index.cfm?question=historicalactivity#:~:text=The%2520Global%2520Volcanism%2520Program%2520does,volcanic%2520activity%2520is%2520actually%2520increasing.&text=The%2520apparent%2520increase%2520in%2520activity,technologies%2520to%2520report%2520those%2520eruptions." target="_blank">Global Volcanism Program</a> say this number is <a href="https://volcano.si.edu/faq/index.cfm?question=historicalactivity#:~:text=The%2520Global%2520Volcanism%2520Program%2520does,volcanic%2520activity%2520is%2520actually%2520increasing.&text=The%2520apparent%2520increase%2520in%2520activity,technologies%2520to%2520report%2520those%2520eruptions." target="_blank">normal</a>.</p><p>HVO confirmed that Kilauea summit eruptions can last more than a decade, based on 200 years of tracking.</p>
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Like many other plant-based foods and products, CBD oil is one dietary supplement where "organic" labels are very important to consumers. However, there are little to no regulations within the hemp industry when it comes to deeming a product as organic, which makes it increasingly difficult for shoppers to find the best CBD oil products available on the market.
<p>Here you can learn about the importance of organic hemp oil, why it's better for the environment, and which CBD companies actually make trustworthy products with sustainable farming processes. origins which weigh heavily on many consumers who want to buy a product that's produced in the best way possible for not only themselves to ingest, but for the environment as well through sustainable farming methods. </p><h2>What Is CBD Oil?</h2><p>First things first, CBD stands for cannabidiol, and it's a cannabinoid found within cannabis sativa plants. This plant compound is believed to have many potential benefits, and it is primarily derived from hemp plants via a CO2 extraction process. </p><p>Since CBD is extracted from industrial hemp, which contains only trace amounts of THC (the psychoactive component in cannabis plants), this means that CBD won't make you feel high like marijuana, which has much higher levels of THC that causes psychoactive effects. Instead, the effects of CBD are much more subtle and promote a general sense of calm and relaxation in most users.</p><h2>What Makes a CBD Oil Organic?</h2><p>In terms of organic labels, perhaps the most important (and prominent) certification comes from the United States Department of Agriculture (USDA). This government organization has been labeling foods as "organic" for many years, but what exactly does this certification entail? Essentially, a label indicating that a product is "USDA Organic" or "Certified Organic" means that at least 95% of the ingredients are obtained from organic sources.</p><p>For a crop to be considered organic by the USDA, it must be grown without the use of industrial solvents, irradiation, genetic engineering (GMOs), synthetic pesticides, or chemical fertilizer. Instead, farmers rely on natural substances and <a href="https://www.usda.gov/media/blog/2012/03/22/organic-101-what-usda-organic-label-means" rel="noopener noreferrer" target="_blank">mechanical, physical, or biologically based farming</a> techniques to cultivate healthy and organic crops.</p><p>Before the passage of the 2018 Farm Bill, no hemp-derived products could be dubbed as "certified organic" since the hemp plant and its extracts were still categorized as a Schedule I Controlled Substance. However, it's still difficult for CBD companies to obtain a USDA certified organic label for their products due to the legal grey area that still surrounds CBD extracts. </p><p>Because of these challenges, and due to the fact that industrial hemp has only recently become an agricultural crop, very few CBD oils are USDA certified organic. Rather, many CBD products contain hemp extracts from plants that were grown in organic conditions but may not be federally certified.</p><h2>What are the Best Organic CBD Oil Brands?</h2><p><em>Each product featured here has been independently selected by the writer. If you make a purchase using the links included, we may earn commission.</em></p><em><br></em>
<h2>Why Organic Hemp Oil Matters</h2><p>Hemp is a unique plant, not only for its rich cannabinoid content, but also for its ability to absorb a wide variety of components in soil. But this trait poses great risks when it comes to the creation of CBD products derived from hemp.</p><p>Because hemp has a high capacity for compound uptake, this means that the plants can retain <a href="https://www.remedyreview.com/industry/lab-test-results/" target="_blank">harmful chemicals like pesticides</a>, heavy metals, and other residual solvents. This is especially true when it comes to synthetic chemicals that are more toxic to humans, and difficult to remove once they have been absorbed by the hemp plant.</p><p>Organic farming practices help reduce the risk of hemp crops absorbing harsh chemicals that may later end up in CBD oil after extraction. When you're taking CBD as a wellness supplement to help alleviate your symptoms or improve your overall well-being, the last thing you want is to ingest compounds that might negatively outweigh the benefits of CBD. This is an important reason to look for third party lab test results when shopping for CBD products since these certificates of analysis can show the full cannabinoid and terpene profile of a hemp extract, as well as test results that search for the presence of any residual solvents.</p><p>In addition to creating a better end product, organic farming practices are also better for the environment. Sustainable and organic farming methods may <a href="https://www.helpguide.org/articles/healthy-eating/organic-foods.htm" rel="noopener noreferrer" target="_blank">reduce pollution, conserve water, reduce soil erosion, increase soil fertility, and use less energy</a>. The use of natural pest deterrents as opposed to chemical pesticides is also better for nearby animal populations and ecosystems.</p><h3>Organic vs. Natural</h3><p>While there are only a select few companies offering certified organic ingredients in their products, almost every brand in the CBD market creates "natural" products. The term "all-natural" or "plant-based" does not mean that a product is organic, and since hemp oil is a natural derivative of hemp plants, these products are often referred to as all-natural. However, there are some synthetic CBD oils that should be avoided because they are chemically constructed and may produce unwanted side effects that are not caused by naturally derived CBD extracts.</p><h2>What are the Benefits of Organic CBD Oil?</h2><p>There's a long list of potential CBD oil health benefits, and some of the most common wellness advantages include:</p><ul class="ee-ul"><li><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2503660/" target="_blank">Chronic pain relief</a></li><li><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4604171/" target="_blank">Anti-anxiety effects</a></li><li>Better sleep</li><li><a href="https://www.psychologytoday.com/us/blog/inner-source/201901/cbd-oil-mental-health-should-you-take-it-too" rel="noopener noreferrer" target="_blank">Improvements in mood</a></li><li>Internal balance and regulation</li></ul><p>When dealing with pain, inflammation, sleep issues, and mental health struggles, it can be hard to find sufficient treatment options. The use of certain prescriptions can cause unwanted side effects, yet they are often the only solution for patients with these medical conditions. In search of other therapies, people have started to flock towards CBD oil as an alternative remedy for a variety of conditions. However, it should be noted that CBD products are not approved by the Food and Drug Administration (FDA), and you should seek your doctor's advice before using CBD if you have a serious medical condition.</p><h2>Look at the Labels Before You Buy CBD Oil</h2><p>When you go online to buy CBD oil, you'll quickly realize there is an overwhelming number of brands that are saturating the market. It can be difficult to determine which products are truly as good as they make themselves out to be. Always look for up-to-date third-party lab tests so you know you are getting a great product, and don't hesitate to contact the brand if you have any additional questions. And if you're intent on purchasing 100% organic CBD oil, it's best to look for certified products or brands that are held to strict regulatory standards.</p><p><strong>Melena Gurganus </strong>is the Reviews Editor at EcoWatch. She is passionate health and wellness and her writing aims to help others find products they can trust. Her work has been featured in publications such as Health, Shape, Huffington Post, Cannabis Business Times, and Bustle.<br></p>
Spruce
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDY4NjI3OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyOTM2NzgzOX0.axY0HjeqRctJsR_KmDLctzDpUBLBN-oNIdqaXDb4caQ/img.jpg?width=980" id="774be" class="rm-shortcode" data-rm-shortcode-id="8379f35b1ca8a86d0e61b7d4bfc8b46e" data-rm-shortcode-name="rebelmouse-image" alt="spruce organic cbd oil" data-width="710" data-height="959" /><p>As one of the best brands in the business, Spruce CBD is well-known for its potent CBD oils that feature many additional beneficial phytocannabinoids. This brand works with two family-owned, sustainably focused farms in the USA (one located in Kentucky and one in North Carolina) to create its organic, small product batches. The max potency Spruce CBD oil contains 2400mg of full-spectrum CBD extract, but the brand also offers a lower strength tincture with 750mg of CBD in total.</p>
$89
CBDistillery
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDcwMjkzNC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyMTU4OTM4Nn0.ypRdeDSBcE87slYrFfVrRwtJ2qGIK6FD5jBB4pndTMo/img.jpg?width=980" id="b473b" class="rm-shortcode" data-rm-shortcode-id="9930b53c9d58cb49774640a61c3e3e75" data-rm-shortcode-name="rebelmouse-image" alt="cbdistillery cbd oil" data-width="1244" data-height="1244" /><p>All of the products from CBDistillery are <a href="https://ushempauthority.org/" target="_blank" rel="noopener noreferrer">U.S. Hemp Authority Certified</a>, and for good reason. The company only uses non-GMO and pesticide-free industrial hemp that's grown organically on Colorado farms. Its hemp oils are some of the most affordable CBD products on the market, yet they still maintain a high standard of quality. CBDistillery has a wide variety of CBD potencies across its product line (ranging from 500mg to 5000mg per bottle) and offers both full-spectrum and broad-spectrum CBD oils to give customers a completely thc-free option.</p>
$35
FAB CBD
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDY4NjIyNS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY2NDIwOTEyMn0.MlTjz096FJ0ev_-soK7_Z-FeQeJczWoeh9Qi9SSkHsY/img.jpg?width=980" id="04b26" class="rm-shortcode" data-rm-shortcode-id="76aa4862f44603242e318982acea6646" data-rm-shortcode-name="rebelmouse-image" alt="fab cbd oil" data-width="800" data-height="800" /><p>For an organic CBD oil that has it all, FAB CBD offers plenty of variety for any type of consumer. All of its products are made with zero pesticides and extracted from organically grown Colorado industrial hemp. FAB CBD oil comes in five all-natural flavors (mint, vanilla, berry, citrus, and natural) and is also available in four strengths (300, 600, 1200, and 2400mg per bottle).</p>
$39
NuLeaf Naturals
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDY4NjIxOS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1NzExNTgyMX0.D6qMGYllKTsVhEkQ-L_GzpDHVu60a-tJKcio7M1Ssmc/img.jpg?width=980" id="94e4a" class="rm-shortcode" data-rm-shortcode-id="3609a52479675730893a45a82a03c71d" data-rm-shortcode-name="rebelmouse-image" alt="nuleaf naturals organic cbd oil" data-width="600" data-height="600" /><p>As an industry-leading brand, it comes as no surprise that NuLeaf Naturals sources its CBD extract from organic hemp plants grown on licensed farms in Colorado. The comany's CBD oils only contain two ingredients: USDA certified organic hemp seed oil and full spectrum hemp extract.</p><p>NuLeaf Naturals uses one proprietary CBD oil formula for all of its products, so you will get the same CBD potency in each tincture (60mg per mL), but can purchase different bottle sizes depending on how much you intend to use.</p>
$38.50
Charlotte's Web
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDcwMjk3NS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0MzQ0NjM4N30.SaQ85SK10-MWjN3PwHo2RqpiUBdjhD0IRnHKTqKaU7Q/img.jpg?width=980" id="84700" class="rm-shortcode" data-rm-shortcode-id="a2174067dcc0c4094be25b3472ce08c8" data-rm-shortcode-name="rebelmouse-image" alt="charlottes web cbd oil" data-width="1244" data-height="1244" /><p>Perhaps one of the most well-known brands in the CBD landscape, Charlotte's Web has been growing sustainable hemp plants for several years. The company is currently in the process of achieving official USDA Organic Certification, but it already practices organic and sustainable cultivation techniques to enhance the overall health of the soil and the hemp plants themselves, which creates some of the highest quality CBD extracts. Charlotte's Web offers CBD oils in a range of different concentration options, and some even come in a few flavor options such as chocolate mint, orange blossom, and lemon twist.</p>
$60
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Fracking Likely Triggered Earthquakes in California a Few Miles From the San Andreas Fault
11 November 2020
Fracking
Activity in the San Ardo oil field near Salinas, California, has been linked to earthquakes. Eugene Zelenko / Wikimedia / CC BY 4.0
Thomas H. Goebel
The way companies drill for oil and gas and dispose of wastewater can trigger earthquakes, at times in unexpected places.
In West Texas, earthquake rates are now 30 times higher than they were in 2013. Studies have also linked earthquakes to oil field operations in Oklahoma, Kansas, Colorado and Ohio.
<p>California was thought to be an exception, a place where oil field operations and tectonic faults apparently coexisted without much problem. Now, new research shows that the state's natural earthquake activity may be hiding industry-induced quakes.</p><p>As <a href="http://www.ceri.memphis.edu/people/thgoebel/" target="_blank">a seismologist</a>, I have been investigating induced earthquakes in the U.S., Europe and Australia. Our latest study, released on Nov. 10, shows how California oil field operations are putting stress on tectonic faults in an area just a few miles from the San Andreas Fault.</p>
<h2>Seismic Surge</h2><p>Industry-induced earthquakes have been an increasing concern in the central and eastern United States for more than a decade.</p><p>Most of these earthquakes are too small to be felt, but not all of them. In 2016, a magnitude 5.8 earthquake damaged buildings in Pawnee, Oklahoma, and led state and federal regulators to <a href="https://apnews.com/article/612b2303f71641f388b0224fb6dab557" target="_blank" rel="noopener noreferrer">shut down 32 wastewater disposal wells</a> near a newly discovered fault. Large earthquakes are rare far from tectonic plate boundaries, and Oklahoma experiencing three magnitude 5 or greater earthquakes in one year, as happened in 2016, was unheard of.</p>
<img lazy-loadable="true" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc3MDc3OS9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYzNDIwNzQ3MX0.oyVDx7o5y5IHAnBtbAdqzNAQYS1LZvhBp6xPtgJeGE4/img.png?width=980" id="26ceb" class="rm-shortcode" data-rm-shortcode-id="4411cc757ff0e66de62ba9ff160cb36b" data-rm-shortcode-name="rebelmouse-image" data-width="1750" data-height="814" />
Chart: The Conversation / CC-BY-ND Source: Thomas Goebel / University of Memphis; Oklahoma Geological Survey Get the data
<p>Oklahoma's earthquake frequency fell with lower oil prices and regulators' decision to require companies to <a href="http://doi.org/10.1126/sciadv.1601542" target="_blank">decrease their well injection volume</a>, but there are still more earthquakes there today than in 2010.</p><p>A familiar pattern has been emerging in West Texas in the past few years: Drastically increasing earthquake rates well beyond the natural rate. A <a href="https://earthquake.usgs.gov/earthquakes/eventpage/us70008ggn/executive" target="_blank">magnitude 5 earthquake</a> shook West Texas in March.</p>
<img lazy-loadable="true" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc3MDc3Ny9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY0MDQ4NDg0OX0.4hR8UHea763EsG79jcducjnOMNXZUThLyRMby98sXq0/img.png?width=980" id="a83bd" class="rm-shortcode" data-rm-shortcode-id="4bf18080b595121783d654bdc7ba43a0" data-rm-shortcode-name="rebelmouse-image" data-width="1744" data-height="844" />
Chart: The Conversation / CC-BY-ND. Source: Thomas Goebel / University of Memphis; U.S. Geological Survey Get the data
<h2>How It Works</h2><p>At the root of the induced earthquake problem are two different types of fluid injection operations: hydraulic fracturing and wastewater disposal.</p><p>Hydraulic fracturing involves injecting water, sand and chemicals at very high pressures to create flow pathways for hydrocarbons trapped in tight rock formations. Wastewater disposal involves injecting fluids into deep geological formations. Although wastewater is pumped at low pressures, this type of operation can disturb natural pressures and stresses over large areas, several miles from injection wells.</p>
<img lazy-loadable="true" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc3MDc2My9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY1NTA2NzQwM30.rC_0BxJ0H-ABMQc_vjlGCFveV_r27xQZxmIcuxDkoCk/img.png?width=980" id="6a3ca" class="rm-shortcode" data-rm-shortcode-id="fc888a37eb478148a0661e75e2518542" data-rm-shortcode-name="rebelmouse-image" data-width="1200" data-height="1972" />
<p>Tectonic faults underneath geothermal and oil reservoirs are often precariously balanced. Even a small perturbation to the natural tectonic system – due to deep fluid injection, for example – can <a href="https://science.sciencemag.org/content/360/6392/1007" target="_blank">cause faults to slip and trigger earthquakes</a>. The consequences of fluid injections are easily seen in Oklahoma and Texas. But what are the implications for other places, such as California, where earthquake-prone faults and oil fields are located in close proximity?</p><h2>California Oil Fields' Hidden Risk</h2><p>California provides a particularly interesting opportunity to study fluid injection effects.</p><p>The state has a large number of oil fields, earthquakes and many <a href="https://maps.conservation.ca.gov/doggr/wellfinder/#openModal" target="_blank">instruments</a> <a href="https://maps.conservation.ca.gov/cgs/fam/" target="_blank" rel="noopener noreferrer">that detect even tiny events</a>, and it was thought to be <a href="https://pubs.geoscienceworld.org/bssa/article-lookup/64/3-1/699" target="_blank" rel="noopener noreferrer">largely free</a> of unnatural earthquakes.</p><p>My colleague Manoo Shirzaei from Virginia Tech and I wondered if induced earthquakes could be masked by nearby natural earthquakes and were thus missed in previous studies. We conducted a detailed seismologic study of the Salinas basin in central California. The study area stands out because of its proximity to the San Andreas Fault and because waste fluids are injected at high rates close to seismically active faults.</p>
<img lazy-loadable="true" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc3MDc2Ni9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYxMzc2Nzk2M30.COB3jmLMt34NtbZ6JMW3bIF6cJ8gtJge8pVOmh1Qkzo/img.png?width=980" id="edc68" class="rm-shortcode" data-rm-shortcode-id="fed3b83d81d884a7b968e4f422f68add" data-rm-shortcode-name="rebelmouse-image" data-width="1200" data-height="886" />
Satellite data shows the ground rising as much as 1.5 centimeters per year in parts of the San Ardo oil field. The line-of-sight velocity (LOS-VEL), as viewed from the satellite, shows how rapidly the ground surface is rising. Thomas Goebel / University of Memphis
<p>Using satellite radar images from 2016 to 2020, Shirzaei made a surprising observation: Some regions in the Salinas basin were lifting at about 1.5 centimeters per year, a little over half an inch. This uplift was a first indication that fluid pressures are out of balance in parts of the San Ardo oil field. Increasing fluid pressures in the rock pores stretch the surrounding rock matrix like a sponge that is pumped full of water. The resulting reservoir expansion elevates the forces that act on the surrounding tectonic faults.</p><p>Next, we examined the seismic data and found that fluid injection and earthquakes were highly correlated over more than 40 years. Surprisingly, this extended out 15 miles from the oil field. Such distances are similar to the large spatial footprint of injection wells in Oklahoma. We analyzed the spatial pattern of 1,735 seismic events within the study area and found clustering of events close to injection wells.</p>
<img lazy-loadable="true" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc3MDc2OS9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY1NDMwOTczOH0.Vyzuv-xFPA78vSmGwpItStBZ_IMxaJSF1p4BKVJxno0/img.png?width=980" id="ea9b2" class="rm-shortcode" data-rm-shortcode-id="e3b1cb09377f14dd6067d9c9e1a48e28" data-rm-shortcode-name="rebelmouse-image" data-width="1200" data-height="986" />
The stresses from injecting water can trigger earthquakes several miles from the well itself. The blue triangles scale with each well's injection rate. Thomas Goebel/University of Memphis / CC BY-ND
<p>Other areas in California may have a similar history, and more detailed studies are needed to differentiate natural from induced events there.</p><h2>How to Lower the Earthquake Risk</h2><p>Most wastewater disposal and hydraulic fracturing wells do not lead to earthquakes that can be felt, but the wells that cause problems have three things in common:</p><ul><li>These are high-volume injection wells;</li><li>They inject into highly permeable rock formations; and</li><li>These formations are located directly above tectonic faults in the <a href="http://doi.org/10.1126/science.aap7911" target="_blank">deeper geologic basement</a>.</li></ul><p>Although the first issue may be difficult to resolve because reducing the volume of waste fluids would require reducing the amount of oil produced, the locations of injection wells can be planned more carefully. The seismic safety of oil and gas operations may be increased by selecting geologic formations that are disconnected from deep faults.<br></p>
<p>
<em>Thomas H. Goebel is an assistant professor of seismology at the Center for Earthquake Research and Information, University of Memphis.<br/>
Disclosure: Thomas H. Goebel receives funding from the U.S. Department of Energy</em>
</p><p>
<em>Reposted with permission from <a href="https://theconversation.com/oil-field-operations-likely-triggered-earthquakes-in-california-a-few-miles-from-the-san-andreas-fault-149207" target="_blank">The Conversation</a></em><em>.</em>
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The 3.6 magnitude quake struck a few miles off the coast of New Bedford, Massachusetts. USGS
The biggest earthquake in decades rattled New England Sunday morning.
<p>The 3.6 magnitude quake was epicentered a few miles off the coast of New Bedford, Massachusetts, <a href="https://www.npr.org/2020/11/08/932784808/earthquake-hits-off-massachusetts-coast-felt-widely-throughout-new-england" target="_blank">according to NPR</a>. No injuries were reported, but 21 people in New Bedford had to evacuate their homes because of minor structural damage, <a href="https://www.nbcboston.com/news/local/earthquake-reported-in-massachusetts-on-sunday-morning/2226075/" target="_blank">NBC10 Boston reported</a>.</p><p>"I've never in my life experienced something so scary, ever in my life," one New Bedford woman told NBC10 Boston. "Like something exploded and I thought like a car had hit my building."</p><p>The quake struck around 9:10 a.m. at a depth of about 9.3 miles. It was felt across Massachusetts and Rhode Island, as well as in parts of Connecticut and Long Island, New York, <a href="https://boston.cbslocal.com/2020/11/08/massachusetts-earthquake-november-8/" target="_blank">CBS Boston reported</a>. Around 14,000 people reported it to the U.S. Geological Survey (USGS) website.</p>
<p>"Earthquakes in this area are commonly felt very far away because the rocks in this area are very contiguous, very old, so they transmit the energy very well from earthquakes," USGS geologist Paul Caruso told <a href="https://www.nytimes.com/2020/11/08/us/earthquake-ma-rhode-island.html" rel="noopener noreferrer" target="_blank">The New York Times</a>.</p><p>Caruso said there had been 26 earthquakes in Southern New England since 1963. However, this was the largest since a 3.5 quake struck in March of 1976, Caruso told CBS Boston.</p><p>"This was the first earthquake I really felt in New England," local seismologist Dr. Alan Kaftka told NBC10 Boston. He said smaller earthquakes in the region were common, but there had only been around nine earthquakes of a similar magnitude since the 1700s.</p>
<p>While no major damage was reported, there was some minor damage. The most dramatic involved collapsed chimneys in two New Bedford apartment buildings, displacing several families. The Red Cross said it was helping 21 people, including children, who had to find another place to stay because of earthquake damage in the city.</p><p>New Bedford Mayor Jon Mitchell said that structural damage was found in at least two homes in the city's South End, CBS Boston reported.</p><p>Meteorologist and Rhode Island native Torry Gaucher tweeted that he found a crack in his basement.</p>
<div id="43e6e" class="rm-shortcode" data-rm-shortcode-id="a3c1f443a75ad15bb139ba1db9178930"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1325454331131392000" data-partner="rebelmouse"><div style="margin:1em 0">Well that is a new stress crack... bummed that my house felt it but I didn’t since I was in the hot tub haha… https://t.co/P6ZraOBfbQ</div> — Torry Gaucher (@Torry Gaucher)<a href="https://twitter.com/TorryGaucher/statuses/1325454331131392000">1604847912.0</a></blockquote></div>
<p>There is also a concern that more damage could be detected as residents turn on their heat for the winter, District Fire Chief James Fortin told NBC10 Boston.</p><p>"Once people start turning on heat, we're afraid that there is going to be damage that people are not aware of and we're going to have an ongoing carbon monoxide issue," he said.</p><p>Both Fortin and Mitchell advised residents to check their carbon monoxide detectors.</p>
<p><br>Earthquake damage exposes the potential danger of <a href="https://www.ecowatch.com/tag/natural-gas" target="_self">natural gas</a> heating.</p><p>"If you smell gas in your house, after turning the heat on or otherwise, evacuate immediately and call 911," Mitchell tweeted Sunday.</p><p>In 2018, a <a href="https://www.ecowatch.com/gas-explosions-massachusetts-2604920740.html" target="_self">series of gas explosions</a> in three towns near Boston injured 25 and killed one person.</p>
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A 3.1 magnitude quake struck Wednesday near Freehold Township, N.J. USGS
A mild but "relatively uncommon" earthquake rattled central New Jersey early Wednesday morning.
<p>The 3.1 magnitude quake lasted 13 seconds and was epicentered about a mile and a half from Freehold Township, U.S. Geological Survey scientist Robert Sanders told <a href="https://www.northjersey.com/story/news/local/new-jersey/2020/09/09/earth-quake-nj-minor-rumbles-felt-nj-2-a-m/5755656002/?_ga=2.13885872.682114553.1599652708-1090369682.1597321798" rel="noopener noreferrer" target="_blank">North Jersey.com</a>. The quake struck around 2 a.m. and was felt throughout central New Jersey and as far away as Philadelphia and Long Island, <a href="https://www.nbcnewyork.com/news/local/usgs-reports-preliminary-3-1-magnitude-earthquake-in-new-jersey/2607680/" rel="noopener noreferrer" target="_blank">NBC4 New York</a> reported.</p>
<div id="55ad7" class="rm-shortcode" data-rm-shortcode-id="f37e5cb897eda103cd0c06d948db03c4"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1303580632577175552" data-partner="rebelmouse"><div style="margin:1em 0">A small tremor occurred in the Freehold area around 2:00 AM. It was felt in much of central New Jersey. #njwx https://t.co/A2axmRkv7v</div> — NWS Mount Holly (@NWS Mount Holly)<a href="https://twitter.com/NWS_MountHolly/statuses/1303580632577175552">1599632816.0</a></blockquote></div>
<p>"It sounded like a dump truck being dropped from a few stories up, but about four to five blocks away," a resident of Matawan, New Jersey wrote on the <a href="https://www.emsc-csem.org/Earthquake/Testimonies/comments.php?id=901071" target="_blank">European-Mediterranean Seismological Center</a>'s (EMSC) earthquake-tracking website, <a href="https://www.nj.com/news/2020/09/31-magnitude-earthquake-reported-in-nj-9-years-after-temblor-shook-state.html" target="_blank">NJ.com reported</a>. "It rumbled the floor for about five seconds. I could feel [it] from my feet on the floor and through the seat of the chair."</p><p>Sanders told NBC4 New York that earthquakes in the area were relatively uncommon. The last time the ground shook significantly within a 10-mile radius of Wednesday's quake was in 1992, when another 3.1 magnitude earthquake was reported. The last time before that was a 3.5 magnitude earthquake in 1979.</p><p>"It will take a few days or weeks before analysts can see if there's a specific fault line at cause here," Sanders said.</p><p>The earthquake prompted at least 125 911 calls in a half-hour period, the Monmouth County Sheriff's Office said. The Freehold Police Department also said its dispatch center received dozens of calls. However, no damage was reported.</p>
<p>"With it being a magnitude of 3.1, a case of injuries is very unlikely," Sanders told NorthJersey.com. "We might have [a] case of items falling off shelves and possibly landing on someone, but typically we don't usually see any widespread damage done with a magnitude this low."</p><p>Many people describing the quake said it did not feel like a typical shaking earthquake.</p><p>"I lived in California and have felt many earthquakes, but I didn't recognize this as one," a Freehold resident wrote on EMSC. "There was no shaking or movement. Just a sound like someone opening up a large sliding glass door followed by two or three very loud banging noises."</p>
<div id="7cc4a" class="rm-shortcode" data-rm-shortcode-id="fc0ef9a7f4b14256185b5968ad096eae"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1303579294841663488" data-partner="rebelmouse"><div style="margin:1em 0">The #earthquake M3.1 In #NJ was well felt within 30 miles of its epicenter. This map represent the eyewitnesses' re… https://t.co/dT0MtwnY8I</div> — EMSC (@EMSC)<a href="https://twitter.com/LastQuake/statuses/1303579294841663488">1599632497.0</a></blockquote></div>
<p>"It's relatively common to hear a loud bang during an earthquake," Sanders told North Jersey.com. "Smaller and more shallow earthquakes have some fault areas and therefore produce high-frequency energy for loud noises. Anyone that is close to the epicenter is likely to hear these effects from the earthquake."</p><p>The last major earthquake to be felt in New Jersey was in 2011, when a 5.8 magnitude earthquake struck in Virginia. That was one of the largest quakes ever recorded in the Eastern U.S. and shook buildings throughout New Jersey, NJ.com reported.</p><p>New Jersey itself is due for a major earthquake, the state's Department of Environmental Protection told NBC4 New York, citing a 5.5 magnitude quake that struck in 1884. It said a similar quake today would cause severe damage and likely claim lives.</p>
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A 7.8 magnitude earthquake struck off the coast of Alaska at 10:12 p.m. local time on July 21, 2020. USGS
Alaskans were rattled by a 7.8 magnitude earthquake Tuesday night that sent people fleeing for higher ground in case of a possible tsunami, before the warning was canceled.
<p>The quake struck offshore at 10:12 p.m. local time and was located around 500 miles southwest of Anchorage and around 60 miles southeast of Perryville, Alaska, <a href="https://www.cbsnews.com/news/earthquake-alaska-tsuani-warning-evacuations-kodiak/" target="_blank">CBS News reported</a>.</p>
<p>"This is a very significant earthquake in size," Alaska Earthquake Center seismologist Michael West told the <a href="https://www.adn.com/alaska-news/2020/07/21/strong-earthquake-prompts-tsunami-warning-from-alaska-peninsula-to-western-kenai/" target="_blank">Anchorage Daily News</a>. </p>
<div id="d0ed7" class="rm-shortcode" data-rm-shortcode-id="ec99e5a42425af683ade8fd6b9374c90"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1285884824293646336" data-partner="rebelmouse"><div style="margin:1em 0">M 7.8 earthquake strikes 105 km SSE of Perryville, Alaska. Tsunami warning canceled. https://t.co/bUwKvi65Lg Le… https://t.co/DlORAa8a2I</div> — USGS (@USGS)<a href="https://twitter.com/USGS/statuses/1285884824293646336">1595413807.0</a></blockquote></div>
<p>The earthquake initially triggered a tsunami warning for South Alaska, the Alaska Peninsula and the Aleutian Islands, CBS News reported.</p>
<p>"Based on the preliminary earthquake parameters... hazardous tsunami waves are possible for coasts located within 300 kilometers of the earthquake epicenter," the Pacific Tsunami Warning Center said, according to CBS News. </p>
<p>The warning prompted evacuations in towns and cities including Kodiak, Sand Point, Unalaska and Homer, the Anchorage Daily News reported. </p>
<p>"We were in a (city) council meeting and started feeling it rocking, and by the time I got home from the council meeting then the warnings were going and had to turn back around," Unalaska City Manager Erin Reinders told the Anchorage Daily News.</p>
<p>Meanwhile, in Kodiak, residents sheltered in Kodiak High School and the local Catholic school while also trying to protect themselves from the coronavirus.</p>
<p>"We've got a high school full of people. I've been passing out masks since the first siren sounded," Kodiak School District superintendent Larry LeDoux told the Anchorage Daily News. "Everything's as calm as can be. We've got probably 300, 400 people all wearing masks."</p>
<div id="2555c" class="rm-shortcode" data-rm-shortcode-id="ff8223dcb0d414e1b97fafad5bfa5fd2"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1285826396325949441" data-partner="rebelmouse"><div style="margin:1em 0">Tsunami warning in kodiak AK https://t.co/pBio9lnWDF</div> — Tyler 🏳️🌈 (@Tyler 🏳️🌈)<a href="https://twitter.com/Tyler82092707/statuses/1285826396325949441">1595399877.0</a></blockquote></div><p>The warnings were canceled by 12:30 a.m. Wednesday. However, a tsunami measuring 0.8 feet was reported in the city of Sand Point, according to CBS.</p><p>Because of its size and characteristics, Tuesday's quake had the potential to be devastating.</p><p>For one thing, it was shallow, measuring six miles, or 10 kilometers, deep, <a href="https://www.cnn.com/2020/07/22/us/alaska-7-8-magnitude-earthquake/index.html" target="_blank">CNN</a> reported. </p><p>"Anything below 70 kilometers is considered a shallow quake," CNN meteorologist Allison Chinchar explained. "That's important, because shallow earthquakes often cause the most damage, compared to the ones that are deeper, regardless of the strength."</p><p>Shallow quakes are also more likely to produce tsunamis, according to the <a href="https://www.usgs.gov/faqs/what-it-about-earthquake-causes-a-tsunami?qt-news_science_products=0#qt-news_science_products" target="_blank">U.S. Geological Survey</a>. </p>
<p>West told the Anchorage Daily News that Tuesday's earthquake was more or less the same type as the Great Alaska Earthquake of 1964.</p>
<p>That earthquake was the strongest ever recorded in North America, with a magnitude of 9.2, CBS explained. The quake and following tsunami killed more than 250 people.</p><p>"These are the style of earthquakes which can be very tsunami-producing," West told the Anchorage Daily News.</p>
<p> The fact that Tuesday's quake occurred offshore reduced shaking, West said. Officials did not think the shaking caused any damage.</p>
<p>"No reports of any damage," Kodiak Police Sgt. Mike Sorter told The Associated Press early Wednesday morning, as <a href="https://www.usatoday.com/story/news/nation/2020/07/22/alaska-earthquake-tsunami-warning/5484967002/" target="_blank">USA TODAY reported</a>. "No injuries were reported. Everything is nominal."</p><p>CNN also reported that more than 20 aftershocks have followed into early Wednesday, ranging in magnitude from 2.8 to 6.1.</p>
<p><em>Correction: An earlier version of this article stated that CNN reported the depth of the quake at six miles. CNN has corrected this number to 17 miles. </em><em>The article has been corrected to reflect this change.</em></p>From Your Site Articles
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Evacuated patients, medical workers and local residents on a street in Mexico City, Mexico, after an earthquake more than 400 miles away rattled the city on June 23, 2020. Francisco Canedo / Xinhua via Getty Images
A powerful earthquake rattled Mexico Tuesday, killing at least six people, Reuters reported.
<p>Mexico's national seismological service said the quake had a magnitude of 7.5 while the U.S. Geological Survey (USGS) put it at 7.4, according to <a href="https://www.nytimes.com/2020/06/23/world/mexico-earthquake.html" target="_blank">The New York Times</a>. It struck around 10:29 a.m. local time and was centered about 14 miles off the Pacific Coast of the southern state of Oaxaca.</p>
<div id="b7545" class="rm-shortcode" data-rm-shortcode-id="b1a86095c21c60b10764f0438784d609"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1275455094117371906" data-partner="rebelmouse"><div style="margin:1em 0">SISMO Magnitud 7.5 Loc 23 km al SUR de CRUCECITA, OAX 23/06/20 10:29:02 Lat 15.57 Lon -96.09 Pf 5 km https://t.co/8uuY2um91w</div> — Sismologico Nacional (@Sismologico Nacional)<a href="https://twitter.com/SismologicoMX/statuses/1275455094117371906">1592927165.0</a></blockquote></div>
<p>Around 200 houses near the epicenter were damaged, a local official told Reuters, 30 severely so.</p><p>"We lost everything in one moment to nature," Vicente Romero, a stationary store owner whose home was significantly damaged, told Reuters. "This is our life's work."</p>
<div id="c4b7f" class="rm-shortcode" data-rm-shortcode-id="0090fcb75028a8f9fcf9b02d7c29defb"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1275468925401042945" data-partner="rebelmouse"><div style="margin:1em 0">#BREAKING: A magnitude 7.4 earthquake strikes Mexico. Look at this video of a building in the area where the earthq… https://t.co/YX3LDJwOnk</div> — Michael Ikahihifo (@Michael Ikahihifo)<a href="https://twitter.com/Mike_Ikahihifo/statuses/1275468925401042945">1592930463.0</a></blockquote></div>
<p>One of the deaths occurred at state-run <a href="https://www.ecowatch.com/tag/oil" target="_self">oil</a> company Pemex, when a worker fell off a refinery structure, <a href="https://www.theguardian.com/world/2020/jun/23/mexico-earthquake-75-magnitude-tremor-hits-oaxaca-state" target="_blank">The Guardian reported</a>. The earthquake also sparked a fire at a Pemex refinery in the Pacific city of Salina Cruz. It injured one worker before it was snuffed out.</p><p>Another person died when a building collapsed in Huatulco, Oaxaca and a third when a house collapsed in the village of San Juan Ozolotepec. A fourth man was killed when a wall collapsed on him in the village of San Agustín Amatengo.</p><p>Despite these individual tragedies, the overall damage was relatively minor.</p><p>"Fortunately there was no major damage," Mexican President Andrés Manuel López Obrador said in a Twitter video reported by The New York Times.</p>
<div id="145c6" class="rm-shortcode" data-rm-shortcode-id="db62988154edbe68d9172f965e88ae6a"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1275480806534701057" data-partner="rebelmouse"><div style="margin:1em 0">Tercer mensaje al pueblo de México tras sismo. https://t.co/5Kn9jPVmu3</div> — Andrés Manuel (@Andrés Manuel)<a href="https://twitter.com/lopezobrador_/statuses/1275480806534701057">1592933296.0</a></blockquote></div>
<p>Obrador said there had been 147 aftershocks as of early Tuesday afternoon.</p><p>"I hope and I wish with all my soul that there will be no more damaging aftershocks," he said.</p><p>Some of the buildings that were damaged included hospitals, The Oaxacan Health Services said, as <a href="https://www.cnn.com/2020/06/23/weather/mexico-earthquake-southern-coast-intl/index.html" target="_blank">CNN reported</a>. Two of the damaged hospitals had been treating <a href="https://www.ecowatch.com/tag/coronavirus" target="_self">coronavirus</a> patients.</p><p>"We are verifying [damages] because this hospital is also tending Covid cases on the Oaxacan coast," Oaxaca state Gov. Alejandro Murat said, as CNN reported.</p><p>The earthquake was felt in Guatemala, Honduras and El Salvador and rattled buildings in Mexico City, more than 400 miles away.</p>
<div id="b04a8" class="rm-shortcode" data-rm-shortcode-id="309c61b1c6d1ee369064ac531c583042"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1275602437475315712" data-partner="rebelmouse"><div style="margin:1em 0">LOOK: A powerful 7.4 magnitude earthquake swayed buildings in Mexico City and sent thousands fleeing into the stree… https://t.co/eoUXH3XN4t</div> — Bloomberg QuickTake (@Bloomberg QuickTake)<a href="https://twitter.com/QuickTake/statuses/1275602437475315712">1592962295.0</a></blockquote></div>
<p>"It really moved," Francisco Aceves, who owns an import-export firm in Mexico City and was on the 22nd floor of an office building when it started, told The Guardian.</p><p>Two people in Mexico's capital were injured and more than 30 buildings were damaged, Reuters reported.</p><p>Mexico is one of the most seismically active countries in the world, according to CNN, because it sits atop three tectonic plates.</p><p>Tuesday's quake comes less than three years after a 2017 earthquake killed hundreds in Mexico City and rendered thousands homeless, <a href="https://www.bbc.co.uk/news/amp/world-latin-america-53160460" target="_blank">BBC News pointed out</a>.</p><p>Also in 2017, Mexico was struck by the strongest earthquake to rattle it in a century when an 8.2 temblor was recorded off the Pacific Coast, according to The New York Times. That earthquake killed at least 90 and mostly impacted the states of Oaxaca and Chiapas.</p><p>Eunice Pineda, a 26-year-old teacher in Juchitan, told Reuters that Tuesday's quake "was two minutes of torture," but she also had adopted a philosophical outlook about the earthquakes that rattle her home.</p><p>"We learn to appreciate, to treasure every moment," she said.</p>
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A seismometer measures the movement of the earth. Gary S Chapman / Getty Images
By Fabian Schmidt
Researchers have discovered an interesting similarity in two of the largest recent earthquakes in Japan and Chile: a strange large-scale ground movement back and forth in the months leading up to the quake.
<p>These earthquakes are among the 10 strongest ever measured: the 2011 Tohoku-oki seaquake off the coast of Japan registered 9.0 on the moment magnitude scale, triggering the devastating tsunami that destroyed the Fukushima Nuclear Power Plant. It was the fourth-strongest quake in the last 100 years. The 2010 seaquake off the coast of the Maule region of Chile, occupies sixth place on the list. </p><p>Researchers from the Geoforschungszentrum Potsdam (GFZ) along with collaborators from Chile and the United States have now discovered astonishing similarities in the months before both quakes: multiple strange reversals of ground motion — an extremely slow "wobbling" of the continental plate, so to speak.</p><p>Lead author, <a href="https://www.gfz-potsdam.de/en/staff/jonathan-bedford/sec41/" target="_blank">geophysicist Jonathan Bedford</a>, along with a team of geodesists, geologists and seismologists, evaluated the movements of ground stations of the Global Navigation Satellite System (GNSS).</p><p>These ground stations continuously track the distances to multiple GNSS satellites that orbit the earth in elliptical orbits. After these distances have been established, and given the estimates of the satellite positions, geodesists are able to define the motion of points on the Earth within a terrestrial reference frame.</p><p>In Japan, there is a very dense network of ground stations. Although the network in Chile was not as dense in 2010, it was sufficient to obtain the data.</p>
Whole Continental Plate 'Wobbles'
<p>Bedford and his colleagues analyzed how the ground stations in Japan and Chile had moved in the five years before the two quakes. They noticed that the motion of the continental plate on which the stations are located had been reversed several times in the last five months before the quake (in the case of Japan) and seven months (in the case of Chile). The researchers published <a href="https://doi.org/10.1038/s41586-020-2212-1" target="_blank">their results</a> in the scientific journal <a href="https://www.nature.com/articles/s41586-020-2212-1" target="_blank">Nature</a>.</p><p>Both plate boundaries are subduction zones. Subduction is the process of one plate diving under another. In both study regions, the oceanic plates are subducting underneath the continental plates and meet at a place called the trench, which for both cases is submerged under the ocean. Normally, the continental plate is pressed by the oceanic plate and thus pushed away from the trench. However, the geophysicists have now discovered that this movement was first reversed in the direction of the trench, then away from the trench, then back towards the trench again.</p>Same Movement Over Thousands of Kilometers
<p>They call this phenomenon "wobbling," due to its appearance in the GNSS time series. The amplitude of this movement is not particularly great — it was only between 4 and 8 millimeters — but Bedford points out that this is significant compared to the relative plate motion that can be a few centimeters per year. Furthermore, the spatial extent of the signal extended thousands of kilometers along the plate boundaries.</p><p>"It is a common assumption that deeper subduction proceeds at a fairly constant speed in between large earthquakes," says Bedford. "Our study shows that this assumption is an oversimplification. In fact, its variability might be a key factor in understanding how the largest earthquakes nucleate." </p><p>With global satellite tracking now becoming better and better, and with accurate data available for the first time in decades, earthquake researchers have an ever-increasing ability to make such observations.</p><p>"We can now trace movements back decades," says Bedford. "In the next stage, we'd like to monitor the changes in near real time."</p>Not Suitable as an Early Warning System
<p>Until now, seismologists have been more able to say <em>where</em> large earthquakes are likely to occur — less able to say <em>when</em>. By simply calculating the magnitude of the last large earthquake in a region and knowing the average relative plate velocity, one can estimate when that fault will be mature enough to sustain a repeat event, although there are great uncertainties in this approach. This is because sometimes a fault will rupture only over a smaller area (e.g. with a "large" magnitude 8 event) and other times it will rupture over many magnitude 8 regions all at once (e.g. in a "mega" magnitude 9 event).</p><p>Could an observed untypical plate movement therefore give us a better warning of an imminent earthquake? Not really. </p><p>"It would not be wise for a geophysicist to issue such a warning," is Bedford's sobering answer. "The observed signals of this study are not necessarily precursory movements of a major quake."</p><p>More research is necessary and as a matter of principle, people in known earthquake areas should not let their guard down. </p><p>"The general public should always be prepared," Bedford warns.</p>
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A USGS map showing the location of a 6.5 magnitude quake that shook Idaho Tuesday evening. USGS
Idaho residents were rattled Tuesday evening by the biggest earthquake to shake the state in almost 40 years.
<p>The 6.5 magnitude quake struck just before 6 p.m. local time 73 miles northeast of Meridian, <a href="https://apnews.com/ee4018c9240bd4768dbea25c40712198" target="_blank">The Associated Press reported</a>. It caused no known damage or injuries, but plenty of surprise. </p>
<p>"At first I thought it was thunder, weird thunder, but then the house was moving and I realized this is an earthquake — a really big earthquake," Boise resident Melissa Hawkins, 44, <a href="https://eu.usatoday.com/story/news/nation/2020/03/31/earthquake-idaho-the-whole-house-rattling/5100853002/" target="_blank">told USA Today</a>.</p><p>All told, more than two million people might have felt the earthquake, according to U.S. Geological Survey (USGS) figures reported by The Associated Press. Reports of shaking came from as far as Spokane, Washington; Bozeman, Montana; and Salt Lake City, Utah, according to USA Today.</p>
<div id="7a1ff" class="rm-shortcode" data-rm-shortcode-id="0e18395a82f4d973bcc848b284b09f44"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1245151137918889984" data-partner="rebelmouse"><div style="margin:1em 0">Here's an interesting visualization of "Did You Feel It?" reports for the #IdahoEarthquake. Head over to the @USGS… https://t.co/dELFgCELYt</div> — Jess Phoenix 🌋 (@Jess Phoenix 🌋)<a href="https://twitter.com/jessphoenix2018/statuses/1245151137918889984">1585702139.0</a></blockquote></div><p>Evaro, Montana resident Shannon Patton at first blamed her health.</p><p>"I actually thought I was having a dizzy spell to begin with due to my migraine," Patton told USA Today in an email. "Our light fixtures were shaking and one of our signs on our pantry door almost fell off."</p>
<div id="80dae" class="rm-shortcode" data-rm-shortcode-id="84f59635d11f02fd671f511c633c6819"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1245138509263859712" data-partner="rebelmouse"><div style="margin:1em 0">Earthquake near Boise, Idaho. Watching now for the four horsemen... https://t.co/qavCnyBGLl</div> — Elaine Ambrose (@Elaine Ambrose)<a href="https://twitter.com/AmbroseElaine/statuses/1245138509263859712">1585699128.0</a></blockquote></div><p>Despite tweets warning of the apocalypse, Caltech seismologist Dr. Lucy Jones told The Associated Press that the Idaho region has an earthquake around this size every 30 to 40 years.</p><p>The last was actually much worse: the 6.9 Borah Peak earthquake of 1983. That quake struck near the town of Challis and killed two school children when they were buried under rubble, <a href="https://edition.cnn.com/2020/03/31/us/idaho-boise-earthquake-trnd/index.html" target="_blank">CNN reported</a>. It also cost the state $12.5 million in property damage.</p><p>The 1983 quake was along a "normal fault," which causes vertical movement, Jones told The Associated Press. Tuesday's quake, on the other hand, was on an unmapped "strike-slip fault," which causes horizontal movement. Jones said it was not uncommon for faults in remote areas to go unmapped, since they are less likely to cause damage.</p>
<p>"This is one that wasn't obvious enough to be mapped before now," Jones told The Associated Press.</p><p>But she further explained on Twitter why Idaho sees earthquakes.</p><p>"Idaho is part of the Basin and Range tectonic province. Everything west of the Wasatch Mtns. is getting slowly stretched out as a bit of North America tries to cling to the Pacific plate," she wrote.</p>
<div id="d9eba" class="rm-shortcode" data-rm-shortcode-id="c0b53a7963c00f719946684fd594c2f1"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1245148206121381889" data-partner="rebelmouse"><div style="margin:1em 0">Idaho is part of the Basin and Range tectonic province. Everything west of the Wasatch Mtns. is getting slowly stre… https://t.co/mmHtOWAeJU</div> — Dr. Lucy Jones (@Dr. Lucy Jones)<a href="https://twitter.com/DrLucyJones/statuses/1245148206121381889">1585701440.0</a></blockquote></div><p>Jones said to expect aftershocks, and the USGS reported a 4.8 magnitude one about an hour after, according to USA Today. More, smaller tremors were felt throughout the evening.</p>
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5.4 Earthquake Rattles Croatian Capital, Forcing Residents out of Coronavirus Lockdown
23 March 2020
Popular
A Croatian fireman walks past rubble in a street of downtown Zagreb, Croatia on March 22, 2020, after a 5.3 magnitude earthquake hit the country. DAMIR SENCAR / AFP via Getty Images
Croatia's capital of Zagreb was rocked Sunday by its strongest earthquake in 140 years, which pushed people out into the streets at exactly the moment they were supposed to stay indoors to fight the spread of the coronavirus.
<p>The earthquake caused widespread damage, injured 17 and forced hospitals to evacuate, <a href="https://www.theguardian.com/world/2020/mar/22/croatia-earthquake-causes-widespread-damage-zagreb" target="_blank">The Guardian reported</a>. But earthquake survivors also had to worry about staying apart while out in the streets.</p><p>"Keep your distance. Don't gather together. We are facing two serious crises, the earthquake and the epidemic," Interior Minister Davor Bozinovic advised, as <a href="https://www.bbc.co.uk/news/world-europe-51995861" target="_blank">BBC News reported</a>.</p><p>Among the locations evacuated was a maternity hospital, according to The Guardian. Mothers and their babies stood outside in a freezing parking lot before the army moved them and their incubators to a new location.</p>
<div id="b4a1a" class="rm-shortcode" data-rm-shortcode-id="e1866f0fe935fa497350b41cc2383e94"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1241704716792406018" data-partner="rebelmouse"><div style="margin:1em 0">A destructive 5.4 magnitude #earthquake hit Zagreb, Croatia this morning - the strongest in 140 years!💔 It breaks m… https://t.co/BffpxXBKXD</div> — Angjelina👼🏻 (@Angjelina👼🏻)<a href="https://twitter.com/angjelinaahmeti/statuses/1241704716792406018">1584880448.0</a></blockquote></div>
<p>The quake was a magnitude 5.4 according to the <a href="https://www.emsc-csem.org/Earthquake/earthquake.php?id=840695#summary" target="_blank">European Mediterranean Seismological Centre</a>, and it rattled the city at 6:24 a.m. local time.</p><p>Initial reports said one 15-year-old was killed, but doctors then said the patient was in critical condition, <a href="https://apnews.com/3f05271ed03ec32a04c96b3587420fdb?utm_campaign=SocialFlow&utm_medium=AP&utm_source=Twitter" target="_blank">The Associated Press reported</a>. The quake also damaged several buildings, including the historic Zagreb cathedral and the country's parliament, The Guardian reported.</p><p>One spire of the cathedral, which was rebuilt following another earthquake in 1880, collapsed, and the parliament building was so badly damaged that its speaker Gordan Jandroković said sessions would have to be postponed.</p><p>"The damage is quite extensive. Walls and stairways have cracked on the upper floor and one section of the roof has been destroyed," Jandroković said.</p>
<div id="2777a" class="rm-shortcode" data-rm-shortcode-id="30e9484c901a58a7cc32467c18798ed7"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1241607134309052418" data-partner="rebelmouse"><div style="margin:1em 0">Zagreb Cathedral tower is damaged https://t.co/Pazq7ghNOp</div> — Ankica Zovko (@Ankica Zovko)<a href="https://twitter.com/anacasey17/statuses/1241607134309052418">1584857183.0</a></blockquote></div>
<p>But the earthquake wasn't the only danger facing Croatians Sunday morning. They also had to consider COVID-19, which has sickened at least 235 people in the country so far. Zagreb is on partial lockdown, The Associated Press reported. Residents had been advised to avoid public places and only gather in groups of five with distance between them.</p><p>Health Minister Vili Beros told residents to stand two meters (approximately 6.6 feet) apart as they waited in the streets.</p><p>"Earthquakes are dangerous, but coronavirus is even more so," Beros said.</p><p>Soldiers wore masks as they shoveled debris.</p><p>The government initially advised people to leave their homes, BBC News reported, but Zagreb's Mayor Milan Bandic then recommended they return home, since 80 percent of Zagreb residents live in structures reinforced with concrete.</p><p>Prime Minister Andrej Plenkovic acknowledged the confusion of the situation.</p><p>"We have two parallel cris[es] that contradict each other," he said, according to The Associated Press.</p>
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Workers evacuate the Lonja del Comercio (Commerce Market) in Havana, Cuba after an earthquake rattled the island Tuesday. ADALBERTO ROQUE / AFP via Getty Images
A 7.7 magnitude earthquake shook the Caribbean Tuesday, rattling people from Miami to Mexico.
<p>The quake struck at 2:10 p.m. and had its epicenter 86 miles northwest of Montego Bay, Jamaica and 87 miles southwest of Niquero, Cuba. It prompted evacuations in Miami and opened sinkholes in the Cayman Islands, but so far there have been no reports of major damages or injuries.</p><p>"This one was serious. It put the fear of God into many people today," Jamaican ad executive Knolly Moses <a href="https://www.npr.org/2020/01/28/800547848/powerful-earthquake-strikes-caribbean-but-no-reports-of-injuries-or-damage?t=1580289383484" target="_blank">told NPR</a>.</p>
<div id="676e5" class="rm-shortcode" data-rm-shortcode-id="T92IQC1580304264"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1222242314346565632" data-partner="rebelmouse"><div style="margin:1em 0">A M7.7 has been reported northwest of Jamaica. It appears to be the transform fault boundary between the North Amer… https://t.co/rc0ZLJi30M</div> — Dr. Lucy Jones (@Dr. Lucy Jones)<a href="https://twitter.com/DrLucyJones/statuses/1222242314346565632">1580240250.0</a></blockquote></div>
<p>The Pacific Tsunami Warning Center initially warned that "hazardous <a href="https://www.ecowatch.com/tag/tsunami">tsunami</a> waves" could impact Belize, Cuba, Honduras, Mexico, the Cayman Islands and Jamaica, <a href="https://www.bbc.co.uk/news/world-latin-america-51287493" target="_blank">BBC News reported</a>. However, those warnings were later withdrawn.</p><p>The earthquake was felt in Kingston, Jamaica and Havana, Cuba. It was also strongly felt in Cuba's largest eastern city, Santiago, The Associated Press reported. However, the colonial city emerged unscathed.</p><p>"It felt very strong but it doesn't look like anything happened," Belkis Guerrero, who works at a Roman Catholic cultural center there, told <a href="https://apnews.com/3666c9ed40bea298b1147d9456eb8230" target="_blank">The Associated Press</a>.</p><p>In the Cayman Islands, the shaking blew the covers off manholes and blasted sewage into the streets, Cayman Islands hospital psychiatrist Dr. Stenette Davis told The Associated Press. The Cayman Islands also felt a series of aftershocks — one reached a magnitude of 6.1. Water was shut off to most of Grand Cayman Island and schools were closed Wednesday.</p>
<div id="b7c0e" class="rm-shortcode" data-rm-shortcode-id="HIJK8N1580304264"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1222252627355820032" data-partner="rebelmouse"><div style="margin:1em 0">Big #earthquake off coast of Jamaica. This photo was taken at Cricket Square in George Town, Cayman Islands. Bricks… https://t.co/wRkDynzr4B</div> — Naomi Yamamoto (@Naomi Yamamoto)<a href="https://twitter.com/naomiyamamoto/statuses/1222252627355820032">1580242709.0</a></blockquote></div>
<p>Cayman Compass editor-in-chief Kevin Morales said that the island was unaccustomed to earthquakes and that newspaper staff were not at first sure what they were experiencing.</p><p>"It was just like a big dump truck was rolling past," Morales told The Associated Press. "Then it continued and got more intense."</p><p>In Miami, meanwhile, the shaking prompted evacuations from at least eight high-rise buildings in downtown Miami, Miami City Commissioner Ken Russell told CNN affiliate WPLG, as the <a href="https://edition.cnn.com/2020/01/28/us/miami-earthquake-evacuations-jamaica/index.html" target="_blank">main network reported</a>.</p><p>High-rise employee Jose Abreu at first thought the vibrations he felt were from a fan.</p><p>"I thought it was the fan acting up on me. I didn't think anything of it," he said. "I just went along, until the building announcement came through the speakers and I just evacuated in the back of the building."</p><p>Ryan Gold of the U.S. Geological Survey told the Miami Herald that it was not surprising that the quake was felt in Miami, as BBC News reported.</p><p>"It's a very large earthquake which can produce a lot of seismic energy," he said.</p>
<div id="b9a63" class="rm-shortcode" data-rm-shortcode-id="V58PU81580304264"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1222249298320089090" data-partner="rebelmouse"><div style="margin:1em 0">Shaking from the 7.7 magnitude Caribbean Earthquake felt in high-rises as far north as Aventura, FL, just north of… https://t.co/bde5Mq68Bc</div> — Brandon Orr (@Brandon Orr)<a href="https://twitter.com/BrandonOrrWPLG/statuses/1222249298320089090">1580241915.0</a></blockquote></div>
<p>The earthquake was also felt in five Mexican states including Veracruz, on the Gulf Coast, The Associated Press reported.</p>
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A crack caused by an earthquake is seen in La Guancha boardwalk in Ponce, Puerto Rico on Jan. 9, 2020. RICARDO ARDUENGO / AFP via Getty Images
By Richard Aster
Multiple strong and damaging earthquakes in southern Puerto Rico starting around Dec. 28, 2019 have killed at least one person, caused many serious injuries and collapsed numerous buildings, including a multistory school in the town of Guánica that luckily was empty at the time. These quakes are the most damaging to strike Puerto Rico since 1918, and the island has been under a state of emergency since Jan. 6, 2020.
<p><br>This flurry of quakes includes onshore and offshore events near the town of Indios and along Puerto Rico's southwestern coast. So far it has included 11 <a href="https://www.usgs.gov/faqs/foreshocks-aftershocks-whats-difference?qt-news_science_products=0#qt-news_science_products" target="_blank">foreshocks</a> – smaller earthquakes that preceded the largest event, or mainshock – with magnitudes of 4 and greater. Major quakes occurred on Jan. 6 (magnitude 5.8) and Jan. 7 (magnitude 6.4 mainshock), followed by numerous large aftershocks.</p><p><a href="https://scholar.google.com/citations?user=khkdN24AAAAJ&hl=en" target="_blank">Seismologists like me</a> are constantly working to better understand <a href="http://www.ecowatch.com/tag/earthquakes">earthquakes</a>, including advancing ways to help vulnerable communities before, during and after damaging events. The physics of earthquakes are astoundingly complex, but our abilities to forecast future earthquakes during a strong sequence of events in real time is improving.</p><p>Forecasting earthquakes is not a strict prediction – it's more like a weather forecast, in which scientists estimate the likelihood of future earthquake activity based on quakes that have already occurred, using established statistical laws that govern earthquake behavior.</p>
<h2>An Undersea Fault Zone</h2><p>Puerto Rico spans a complex boundary between the Caribbean and North American <a href="https://pubs.usgs.gov/gip/dynamic/tectonic.html" target="_blank">tectonic plates</a>, which are sliding past each other in this region at a relative speed of about 2 centimeters per year. Over geologic time, this motion has created the Muertos Trough, a <a href="https://seismo.berkeley.edu/blog/2020/01/07/deadly-earthquakes-in-the-muertos-trough.html" target="_blank">15,000-foot depression in the sea floor</a> south of the island.</p><p>This plate boundary is riddled with interconnected fault structures. The present activity is occurring on and near at least three interrelated large faults.</p>
<img lazy-loadable="true" src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjUwNzkwMi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxMzM2OTQ1M30.C0LJHoMTL55fyQZTmDiwfJoDGDE7LL05nkvSztuLjvY/img.jpg?width=980" id="9c749" class="rm-shortcode" data-rm-shortcode-id="35f84d58ad0b90d9de549e5688b53c59" data-rm-shortcode-name="rebelmouse-image" />
Multiple faults crisscross the eastern Caribbean. Those outlined in red have a potential to generate a large earthquake. The arrow at top right shows the direction of the North American plate's motion relative to the Caribbean plate. Red stars denote intensity centers for past earthquakes. USGS
<p>Faults are pre-existing weak zones between stronger rocks. In response to surprisingly small force (stress) changes, they rapidly slip to produce earthquakes. The "hair-trigger" nature of fault slip means that predicting the precise timing, location and size of individual quakes is extremely challenging, if not impossible.</p><p>During an earthquake sequence, changing stresses act on nearby fault systems as stress is gradually redistributed within the earth. This process generates thousands of protracted aftershocks.</p><p>Many earthquake sequences simply start with the mainshock. But it is not especially rare for scientists to recognize after the fact that foreshocks were occurring before the main event. Improvements in earthquake instrumentation and analysis are helping scientists detect foreshocks more often, although we have not yet figured out how to recognize them in real time.</p>
<h2>Will One Shock Lead to Another?</h2><p>Researchers have known for over a century that the rate of earthquakes following a mainshock declines in a way that we can characterize statistically. There is also a well-established relationship between the magnitude of earthquakes and their relative number during an earthquake sequence. In most seismically active regions, for a decrease of one magnitude unit – say, from 4.0 to 3.0 – people can expect to experience about 10 times as 3s compared to 4s in a given time period.</p><p>Using such statistical relationships allows us to forecast the probability and sizes of future earthquakes while an earthquake sequence is underway. Put another way, if we are experiencing an aftershock sequence, we can project the future rate of earthquakes and what magnitudes we expect those quakes to have.</p>
<p>
<em>Richard Aster is a professor of geophysics and the department head at Colorado State University.<br/>
</em><em>Disclosure statement: Richard Aster has received funding for earthquake research from the National Science Foundation, Los Alamos National Laboratory, Sandia National Laboratories and the U.S. Geological Survey. He is a past president of the Seismological Society of America (SSA) (2009-2011) and current chair of the board of directors of Incorporated Research Institutions for Seismology. Aster also chairs the U.S. Geological Survey's Advanced National Seismic System Advisory Committee, and is a member of the Southern California Earthquake Center Advisory Council.</em>
</p><p>
<em>Reposted with permission from <a href="https://theconversation.com/earthquake-forecast-for-puerto-rico-dozens-more-large-aftershocks-are-likely-129874" target="_blank">The Conversation</a>.</em>
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