Articles tagged with Subduction
A new analysis reveals that massive earthquakes on the Cascadia Subduction Zone, affecting population centers like Portland and Seattle, may occur more frequently than thought. The study used detailed data from core samples and found slightly higher chances of an earthquake within the next 50 years.
Researchers found that calcareous sediments, not clay-rich sediments, are the most likely candidates for the first breakage of an earthquake. The study suggests that these sediments form a weak point in the rock sequence, leading to shallow earthquakes and tsunamis.
Researchers used electron backscatter diffraction to unravel the transformations involved in creating granular zircon. The results show that making granular zircon first involves forming twins and transforming into reidite under extreme pressure and temperature conditions.
The August issue of Lithosphere presents papers on Tyrrhenian margin neotectonics in Italy, the Wrangellia composite terrane in Canada, and fault-related fissures in Wales. These studies provide new insights into Quaternary travertine deposits, thermochronology data, and paleofluid circulation in faults.
Researchers are analyzing data from the September 16, 2015 magnitude 8.3 earthquake in Illapel, Chile, to gain insights into the boundary's dynamics and predict future earthquakes. The study aims to map out strain release, identify active faults, and describe deformation of the top plate.
Scientists have identified a subduction zone beneath Bangladesh, where two tectonic plates are slowly thrusting under each other. The resulting strain could lead to an earthquake magnitude of up to 9, affecting over 140 million people in the region.
A slow slip event in New Zealand's Hikurangi margin showed that subduction plates may be accumulating much more stress and strain than previously thought. This finding helps assess earthquake occurrence risk in coastal areas near subduction zones, especially at locations of shallow depth.
Researchers have discovered a slow-slip event that lasted two weeks, resulting in 15-20 centimeters of movement along the fault. The finding increases understanding of the relationship between slow slip and normal earthquakes, highlighting the potential for using offshore monitoring systems to predict damaging earthquakes.
A magnitude 7.1 earthquake in January's Iniskin event shook the Cook Inlet region of Alaska, prompting seismologists to revise their estimates of intermediate-depth earthquakes in the area. The quake's unusual depth of 123 km below the surface resulted in minimal damage, but could affect future hazard risk estimates in southern Alaska.
Researchers propose a new conceptual model for monogenetic eruptions, suggesting seismic crises occur before eruption and magmatic intrusions play a key role. This framework could improve forecasting of these events in populated areas, reducing economic and societal impact.
Geologists from Brown University have discovered that water escaping from mineral lawsonite at high temperatures and pressures makes it prone to brittle failure, triggering earthquakes. This explains why certain quakes occur in cold subduction zones where lawsonite forms, but not in hot zones.
Scientists have discovered geological evidence of frequent large tsunamis in the Aleutian Islands, posing a new hazard to the Pacific basin. The study reveals that a creeping section of the Aleutian Subduction Zone fault could generate earthquakes great enough to trigger devastating tsunamis.
A recent study on the 2015 Nepal earthquake highlights the potential risks of landslides in the Pacific Northwest. The research team estimated tens of thousands of landslides, causing widespread damage and loss of life.
Researchers at Johannes Gutenberg University Mainz found that the appearance of blueschist, a blue-violet rock, is connected to long-term changes in the composition of the oceanic crust. This discovery challenges theories on the emergence of plate tectonics, which previously dated back to the Neoproterozoic era or even earlier.
Scientists have observed unusual seismic wave speeds that suggest the frozen olivine structure within the flat-slab slab has vanished and been replaced by a new unexpected structure. This implies that slabs are weak enough to deform internally in the upper mantle over time.
Researchers found that a deep-seated slab beneath Peru's Nazca Plate deforms easily during subduction, weakening its internal structure. The study sheds new light on the behavior of oceanic slabs in the Earth's interior.
Researchers at the University of Liverpool have discovered a previously undetected earthquake that occurred just 12 seconds after a magnitude 7 earthquake in Chile. The 'closely-spaced doublet' increases the risk of larger-than-expected tsunamis, complicating tsunami early warning systems.
Researchers propose that mantle plumes played a crucial role in initiating plate tectonics on Earth. Computer simulations suggest that plume-induced weaknesses in the lithosphere could have led to the formation of subduction zones and the emergence of modern plate boundaries. The study provides a possible explanation for the early hist...
A team of international researchers suggests that a large and hot mantle plume was necessary to break the early Earth's lithosphere, leading to the first subduction and Plate Tectonics. The conditions required for this process included a thick and heavy lithosphere, liquid water in the oceans, and a large enough plume to produce signif...
A team of scientists has mapped the mantle under the Juan de Fuca plate, a key step in understanding the forces behind large earthquakes and tsunamis. The map reveals segmentation of the subduction zone, which could help explain why Pacific Northwest megaquakes don't always break along the entire length.
A new study presents a method using GIS and National Geothermal Data System data to evaluate regions for geothermal energy exploration. The Denver-Julesberg Basin is identified as the highest capacity for large-scale, economically feasible geothermal power production.
A Northwestern University expert found mixed results on human preparedness for tsunamis, with significant progress made in tsunami science and education. However, substantial challenges remain, including the impact of 'tsunami earthquakes' and the need to incorporate new knowledge into warning procedures.
The Chinese continental shelf's basement is of exotic origin, unrelated to eastern China's continental lithosphere. Subduction cessation at ~100 Ma jammed the trench, altering Pacific plate motion and forming a transform boundary.
Researchers have recalculated the frictional strength of subduction zone faults worldwide, revealing low stresses in these areas despite potential for large earthquakes. The study suggests that even weak faults can accumulate stress to produce significant quakes.
The Cascadia Initiative has deployed seismometers onshore and offshore to monitor the Cascadia subduction zone. The project provides a clearer picture of the region's seismic risk, including undetected small earthquakes and new offshore structures. The initiative also offers insights into tsunami detection and seismic wave readings.
Researchers used seismometers to study Peruvian flat slab subduction, revealing its structure and evolution over time. The team found the angle of subduction is shallowest near the Nazca Ridge, where the plate sinks 90 km down before flattening out.
Researchers studied earthquake history in the eastern Indian Ocean, tracing modes of coastal sedimentation over time. They discovered seven subduction zone earthquakes recorded 3,800 to 7,500 years ago, indicating past tsunamis occurred approximately four to six times.
Dr. Hiroo Kanamori received the Marcus Milling Legendary Geoscientist Medal for his pioneering discoveries in understanding large earthquakes and developing scaling relations between earthquake parameters. His work has allowed geoscientists to better predict tsunami-prone communities.
Researchers have uncovered evidence of ancient earthquakes on New Zealand's southern Hikurangi margin, suggesting shorter time intervals between large quakes than previously thought. The findings confirm a previously assumed risk and may help better understand earthquake hazards in the region.
Research at ETH Zurich reveals that wider seismogenic zones increase the probability of a supercycle occurring, characterized by several large earthquakes and eventually a giant earthquake. The study proposes a new explanation for the gradual rupture phenomenon, suggesting that physical stresses build up rapidly at the edges of the zone.
MIT researchers explain India's rapid move toward Eurasia 80 million years ago by the combination of two subduction zones. The team found relics of what may have been two subduction zones in rocks from the Himalayan region, which led them to develop a model for a double subduction system.
A recent study on the 2012 Mw 7.8 Haida Gwaii and 2013 Mw 7.5 Craig earthquakes reveals a confirmed subduction zone in the Haida Gwaii area, complicating seismic hazard assessments for British Columbia and Alaska. The research also found that the mainshock altered stress fields in the rupture zone, leading to normal faulting behavior.
Unaweep Canyon, the only canyon with two mouths, formed in multiple stages ~300 million years ago. The inner gorge was incised by the Gunnison River as part of the incision of the Colorado Plateau, linking events on the northern and southern Plates. This study highlights the preservation of ancient landscapes from Earth's deep-time past.
Research finds that the Darrington-Devils Mountain fault zone is prone to strong earthquakes, with evidence of a M 6.7 to 7.0 quake 2,000 years ago and another at 8,000 years old. This suggests a right-lateral slip sense during past earthquakes, which may be related to ongoing clockwise rotation in the region.
The nation's first tsunami evacuation refuge is being built in Washington state to shelter over 1,000 people within a 20-minute walking distance. The vertical structure will be the roof of an elementary school gym, designed to withstand massive earthquakes and storm surges.
Recent great earthquakes have provided unprecedented insights into seismic activity, highlighting the complexities of ruptures and interactions with surrounding regions. The study focuses on Cascadia, where advances in technology and scientific capacity enable a better understanding of future earthquake risks.
New research provides estimates for probable maximum magnitude events in subduction zones for various time periods, including 250, 500 and 10,000 years. Most subduction zones can generate M 8.5 or greater over a 250-return period; M 8.8 or greater over 500 years; and M 9.0 or greater over 10,000 years.
Researchers used leaf vein density to study stratified forests with canopy-dominant flowering plants. They found that venation density is higher in leaves from the forest canopy and decreases towards lower levels. This pattern suggests that flowering plants emerged in the upper forest canopy by the Paleocene, around 58 million years ago.
Researchers analyzed near-real-time data from the April 1 earthquake in Iquique, Chile, and found that it occurred on a fault gap not ruptured since 1877. The study suggests that while the current stress was not released during the quake, it leaves open the possibility of another significant event.
Researchers have discovered an ancient Hawaiian volcano, named Ka'ena, which is believed to be the first building block for the island of O'ahu. The study provides compelling evidence that Ka'ena's lava chemistry and volcanic evolution played a crucial role in shaping the island's landscape.
A team of scientists used computer modeling to reveal how giant swirls form during plate collision, explaining the origin of curved mountain chains along subduction zones. The model suggests that parts of the subducted slab sweep around behind the collision, pushing continental material into the mountain belt.
Researchers investigate parallel mountain chains, rift flank uplift, and unique episodes in Earth's history. They use computer models and experimental data to understand the timing of uplift and crustal extension during rifting processes.
Researchers accurately predicted the magnitude 7.6 Nicoya earthquake in Costa Rica, allowing for improved building codes and reduced damage. The study used GPS data to map out the likely extent of an earthquake rupture along a subduction megathrust, providing valuable insights into plate tectonics.
Researchers have developed a new global map to predict giant earthquakes at subduction zones, including the Australian region. The study identified several regions capable of producing massive earthquakes, while others are not predicted to experience such events.
Scientists have made significant findings on continental subduction, revealing the processes that occur within subduction channels and their impact on collision orogeny. These studies focus on the interaction between the deeply subducted crust and the overlying mantle wedge under ultrahigh pressure conditions.
The journal Geology has published new articles on various geoscience topics, including the tracking of silicic magma reservoirs and thermal decomposition along natural carbonate faults during earthquakes. The studies provide valuable information about the chemical and thermal histories of magmatic systems.
A new subduction zone has been detected off the coast of Portugal, marking the beginning of a cycle that will close the Atlantic Ocean. The Iberian subduction zone will pull Iberia towards the United States over approximately 220 million years.
A new study analyzes geologic records to predict megathrust earthquakes along Canada's west coast. The research identified 22 earthquake shaking events over the past 11,000 years, with a recurrence interval of about 500 years. This study helps Canadian coastal communities improve hazard assessments and emergency preparedness plans.
Studies reveal CO2 gas following seismic swarms, growth of Mount Everest, and remarkably modern Cretaceous seawater composition. Loess paleosol sequences in central Europe provide insights into the progressive evolution of a continental climate during the Middle Pleistocene.
Studies in Western Europe reveal local forces driving tectonic activity, while a paper on the Osa Peninsula describes rapid vertical deformation of crustal blocks. Another study examines the extension of an orogenic wedge through the exhumation of high-pressure terranes in Norway.
Researchers used GPS data to measure ground deformation caused by a large underwater earthquake, providing accurate warning of the resulting tsunami in just a few minutes. This method can provide fast, detailed, and accurate tsunami alerts, overcoming limitations of traditional seismological methods.
Researchers from the University of Pennsylvania used a fossil-based technique to study the 1700 Cascadia earthquake and its impact on coastal land levels. The study revealed that the rupture was heterogeneous, similar to recent major earthquakes in Japan, Chile, and Sumatra.
A recent study suggests the Makran subduction zone, beneath the Arabian Sea, has a higher potential for major earthquakes and tsunamis than previously thought. This could threaten the coastlines of Pakistan, Iran, Oman, and India.
The 2011 Tohoku earthquake and tsunami are the subject of a special issue in the Bulletin of the Seismological Society of America. Researchers investigated the rupture process, seismic radiation, geodetic deformations, and tsunami waves. The study sheds light on the processes at work during giant earthquakes.
Researchers explore ancient iron oceans, Antarctic climate feedbacks and evidence of catastrophic spillover from Mars. High-resolution imagery reveals standing bodies of water in eastern Valles Marineris region of Mars.
A team of international researchers led by University of Rhode Island Professor Christopher Kincaid found that severely deformed and defunct pieces of a former mantle plume caused volcanism in the Yellowstone area. The study suggests that circulation currents driven by tectonic plate movement at subduction zones affected the plume, pro...
The North American Cordillera is composed of dozens of crustal blocks that were welded onto the continent over 200 million years. A new study clarifies their mode of origin, identifying a previously unknown oceanic plate that contributed to their assembly.
Researchers studied detrital zircon Hf isotopic compositions to connect the Alexander terrane in Canada with northern Caledonian granitoids. In California, a kinematic analysis of mélange fabrics near San Simeon reveals sinistral slip on the Nacimiento fault zone. The Western Alps also experienced short-lived fast erosional exhumation ...
Researchers have found that basin sediments recorded the formation process of the Dabie orogen, providing crucial information on subduction and rapid exhumation. The study suggests a gradual transition from shortening to extension during the Mesozoic era, with the depth of exhumation increasing eastwards.
A recent study published in Science investigates the stress state on the fault that controls a very large slip during an earthquake. The research found that the present shear stress on the fault is nearly zero, indicating a nearly complete stress change during the earthquake.