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Categories: Geoscience: Earthquakes

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     (via sciencedaily.com)     Original source 

Using remote sensing, geophysicists have documented the massive Feb. 6 quake that killed more than 50,000 people in Eastern Turkey and toppled more than 100,000 buildings. Alarmingly, researchers found that a section of the fault remains unbroken and locked -- a sign that the plates there may, when friction intensifies, generate another magnitude 6.8 earthquake when it finally gives way.

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Even though most of the economic losses are concentrated in California and along the West Coast due to that region's high seismic hazard levels, significant population, and building exposure, earthquake risk is spread throughout the country. For example, there is a combined $3.1 billion per year in projected losses across the central U.S., Rocky Mountain region, Alaska, Hawaii, Puerto Rico and the Virgin Islands.

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Earthquakes and volcanism occur as a result of plate tectonics. The movement of tectonic plates themselves is largely driven by the process known as subduction. The question of how new active subduction zones come into being, however, is still under debate. An example of this is the volcanic Lesser Antilles arc in the Caribbean. A research team recently developed models that simulated the occurrences in the Caribbean region during the Cretaceous, when a subduction event in the Eastern Pacific led to the formation of a new subduction zone in the Atlantic. The computer simulations show how the collision of the old Caribbean plateau with the Greater Antilles arc contributed to the creation of this new Atlantic subduction zone. Some 86 million years ago, the triggered processes subsequently resulted in a major mantle flow and thus to the development of the Caribbean large igneous province.

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Oceanographers discovered warm, chemically distinct liquid shooting up from the seafloor about 50 miles off Newport. They named the unique underwater spring 'Pythia's Oasis.' Observations suggest the spring is sourced from water 2.5 miles beneath the seafloor at the plate boundary, regulating stress on the offshore subduction zone fault.

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Researchers used small zircon crystals to unlock information about magmas and plate tectonic activity in early Earth. The research provides chemical evidence that plate tectonics was most likely occurring more than 4.2 billion years ago when life is thought to have first formed on our planet. This finding could prove beneficial in the search for life on other planets.

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After an earthquake, it is crucial in the early phase of disaster management to obtain a rapid assessment of the severity of the impact on the affected population in order to be able to initiate adequate emergency measures. A first quick and good assessment of whether an earthquake causes severe or minor damage can often be given after only 10 minutes by information from affected people about the 'felt intensity' of the earthquake.

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A new study suggests there may be a layer of surprisingly fluid rock ringing the Earth, at the very bottom of the upper mantle.

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Data captured from seismic waves caused by earthquakes has shed new light on the deepest parts of Earth's inner core, according to seismologists.

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New research on friction between faults could aid in predicting the world's most powerful earthquakes. Researchers discovered that fault surfaces bond together, or heal, after an earthquake. A fault that is slow to heal is more likely to move harmlessly, while one that heals quickly is more likely to stick until it breaks in a large, damaging earthquake. Tests allowed them to calculate a slow, harmless type of tremor. The discovery alone won't allow scientists to predict when the next big one will strike but it does give researchers a valuable new way to investigate the causes and potential for a large, damaging earthquake to happen, and guide efforts to monitor large faults like Cascadia in the Pacific Northwest.

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Cornell University researchers have unearthed precise, microscopic clues to where magma is stored, offering a way to better assess the risk of volcanic eruptions.

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Scientists have discovered a new layer of partly molten rock under the Earth's crust that might help settle a long-standing debate about how tectonic plates move. The molten layer is located about 100 miles from the surface and is part of the asthenosphere, which is important for plate tectonics because it forms a relatively soft boundary that lets tectonic plates move through the mantle. The researchers found, however that the melt does not appear to notably influence the flow of mantle rocks. Instead, they say, the discovery confirms that the convection of heat and rock in the mantle are the prevailing influence on the motion of the plates.

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A 'back-projection' technique reveals new details of the volcanic eruption in Tonga that literally shook the world.

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New findings begin to fill major gaps in understanding about how geological faults behave and appear as they deepen, and they could eventually help lead future researchers to develop better earthquake models on strike-slip faults, regions with frequent and major earthquakes.

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A new study has found that individuals from disadvantaged backgrounds are more likely to experience disaster-related home loss, and they are also more likely to develop functional limitations following the disaster. 

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A machine-learning algorithm reveals the shape of massive subterranean structures linking active volcanoes.

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Researchers suggest how scientists can circumvent the need for massive data sets to forecast extreme events with the combination of an advanced machine learning system and sequential sampling techniques.

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A study has shown that the prevalence of non-communicable diseases, which included hypertension, hyperlipidemia, diabetes, and mental disorders, increased after the Fukushima disaster and the COVID-19 outbreak. These findings emphasize the importance of improving post-disaster health promotion strategies and recommendations.

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Evidence that a complete stress release may have contributed to the 2011 Tohoku earthquake that broke records. Both sedimentary formations above and below the plate boundary fault lie in the stress state of normal faults in which vertical stress is greater than maximum horizontal stress. The new data show good consistency with previous results above the fault -- at the boundary between the North American plate and the subducting Pacific plate -- suggesting that combining geophysical data and core samples to comprehensively investigate stress states is effective.

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Satellite observations have revealed that weak seismic ground shaking can trigger powerful landslide acceleration -- even several years after a significant earthquake.

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Earthquakes are notoriously hard to predict, and so too are the usually less-severe aftershocks that often follow a major seismic event.