Articles tagged with Subduction
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.
Researchers, led by Chris Goldfinger, admit that existing predictive models are no longer valid due to limited historical records. Paleoseismic evidence suggests that several regions previously thought incapable of producing megathrust earthquakes may be due for reconsideration.
Researchers have discovered that some of the tectonic processes driving volcanic activity were occurring as early as 3.8 billion years ago. The study found compositions comparable to modern oceanic islands in ancient rocks, strengthening arguments for subduction-related tectonics.
Researchers found that 87% of large (8.6 magnitude or higher) earthquakes are associated with intersection regions between oceanic fracture zones and subduction zones. This connection is less striking for smaller earthquakes, which are more common.
Scientists at Stanford University have identified segments of the Main Himalayan Thrust fault that could lead to massive earthquakes in the Himalayas. Meanwhile, researchers are studying small tremors in the Cascadia subduction zone to improve earthquake prediction and mitigation strategies for the Pacific Northwest.
Research in the Russian Far East has revealed a seismic and volcanic hotbed, with potential to trigger tsunamis that affect the entire Pacific Basin. Thousands of people were killed in tsunamis due to earthquakes in the region, highlighting the importance of studying these hazards.
The North China Craton's thin lithosphere and signs of thermo-tectonic reactivation challenge the traditional view of a stable cratonic lithosphere. The concept of 'craton destruction' has been widely accepted, influencing understanding of intraplate magmatism and continental evolution.
The study analyzes the Taiwan mountain belt to understand the initial formation of topographic curvature in a geologically young region. It also presents new U-Pb zircon ages for rocks in the Jurassic Bonanza arc, Vancouver Island, Canada, shedding light on the timing and character of ancient volcanic and plutonic activity.
A magnitude 8.6 earthquake in the East Indian Ocean triggered quakes around the world for at least a week, according to a new analysis. The study found that some faults weren't immediately affected by seismic waves but were primed to break up six days later.
Researchers investigate debris flow impacts on alpine denudation rates and find that large events can significantly perturb cosmogenic denudation rates. Mid-Pacific microatolls provide a record of sea-level stability over the past 5000 years, indicating minimal oscillations in recent millennia.
A comprehensive study of tsunamis in Northwestern California has been compiled by UCSB scientists, revealing evidence of smaller strong-to-major earthquakes and larger quakes that involved the regional subduction zone. The research provides valuable insights into the region's seismic activity and potential for future tsunami events.
Scientists uncover bacterial fossils in ancient rocks, revealing clues about life on Mars and the formation of iron oxide minerals. Researchers also study volcanic fields to predict future eruptions and develop warning systems for high-population zones and remote communities like Tristan da Cunha.
Researchers have discovered that Mars' interior contains more water than previously thought, with implications for the planet's geological history. Additionally, a study of ancient stromatolites suggests that reef-building may have occurred earlier than previously believed, challenging current models of ecosystem development.
Researchers analyze seismic data from India to understand past and present Earth dynamics. They also discuss the importance of studying forearc crust and ophiolites to understand subduction zone formation. Additionally, experiments reveal the melting of sediments at high pressures and temperatures.
This new research presents a well-documented ancient sedimentary record of subduction initiation in California, shedding light on the beginning of this process. The study also provides insights into the Karakoram Fault Zone in Tibet and updates the understanding of the Walker Lane belt in Nevada.
A new study evaluates seismic hazards for six capital cities in Central America, with Guatemala City and San Salvador at highest risk. The study provides a regional seismic catalog and strong motion database updated to December 2010, supporting national seismic code revisions.
Researchers are conducting a seismic survey at the Mariana trench to map the distribution of serpentinite in subducting plates and overlying mantle. This will help understand island-arc volcanism and subduction-zone earthquakes, which are among the most powerful in the world.
Researchers will monitor the Cascadia subduction zone's strain buildup using a new seafloor geodesy observatory. This data will aid in modeling fault slip and predicting tsunami heights, ultimately informing city planners and emergency response managers.
The University of Washington is developing an early earthquake warning system with a $2 million grant from the Gordon and Betty Moore Foundation. The system will place sensors along the coast to record the first signals from a major earthquake on the Cascadia subduction zone, providing warning for very large coastal earthquakes.
Researchers develop three-dimensional model to explain Andes formation, predicting earthquakes and mountain range evolution. The new approach improves predictive power, allowing scientists to forecast tectonic plate behavior.
Researchers have collected rare boninite lava at the West Mata volcano, providing valuable insights into the formation and evolution of subduction zones. The discovery offers a unique opportunity to study the chemical and mineralogical variations of this ancient rock type in a pristine specimen.
Researchers found diverse mineralogies in two troughs of Noctis Labyrinthus, Mars, indicating a potentially habitable environment and liquid water presence. Additionally, studies on EarthScope seismic observations and the formation of high delta18O fayalite-bearing A-type granite reveal key factors for these unique rock types.
A team of scientists has created a curved cross-section of the North American continent, extending from the Cascadia subduction zone to the Atlantic margin. The cross-section reveals scars of ancient continental collisions and eons of oceanic subduction, indicating processes that have shaped the continent for over three billion years.
Researchers found that episodic tremors can reverse direction and travel back through fault lines much faster than the original rupture. The event was observed in the Pacific Northwest region, particularly in Washington state, and released as much energy as a magnitude 6.8 earthquake.
Researchers found widespread soil liquefaction in Japan, exceeding expectations, and raising concerns about its impact on vulnerable locations such as Portland, Ore. and the Pacific Northwest. The phenomenon can cause structures to shift or sink, significantly magnifying damage.
Researchers studied freshwater fish fossils to understand the Neogene water cycle in Central Africa. A study proposed that Nuna was Earth's first supercontinent. Ancient cave systems near the Allgau Mountains preserved the oldest radiometrically dated dripstones known in the European Alps.
Experts gather to discuss the state of knowledge about the New Madrid Seismic Zone, a region prone to large earthquakes with significant economic losses. Researchers also explore computer simulations of earthquake ground motion in the zone, aiming to understand and anticipate future events.
This issue of GSA Bulletin explores river geomorphology, submarine landslides, and paleoclimatic analysis. Researchers examine the impact of a dome-building eruption on downstream channel aggradation in Oregon, as well as the age and genesis of the Sangamon/Loveland complex in the Lower Mississippi Valley.
Recent studies by University of Rhode Island scientist Katherine Kelley reveal that the Earth's mantle is highly oxidized due to exposure to oxygen during its formation. The findings suggest that oxygen from subduction zones controls mineral composition and gas behavior in the mantle, influencing volcanic eruptions.
Researchers are using an array of seismic sensors to study unfelt seismic tremor events, revealing a more complex relationship with potentially devastating earthquakes. By analyzing the movement of these tremors, scientists are gaining insights into the Cascadia subduction zone and its potential for massive quakes.
A team of geophysicists led by Harry Green at UC Riverside presents evidence contradicting the widely-held view that large amounts of water are carried to the deep mantle in subducting slabs. The study suggests that these slabs are essentially dry, with no pathway for significant amounts of water to enter the lower mantle.
Researchers have developed a dynamic model to explain Mount Etna's existence, suggesting it resulted from decompression melting of upper mantle material. The theory provides an alternative explanation for the volcano's geological environment and surrounding volcanism.
This article highlights various scientific discoveries in September 2010 Geology, including a study on Neoproterozoic ice ages and their impact on the environment. Researchers also investigate stress-driven failure during fracture array growth and explore the relationship between Antarctic glaciation and tropical rain belt migration.
A magnitude-8.1 earthquake triggered two major quakes of magnitude 7.8 within two minutes, affecting Samoa, American Samoa, and Tonga, with water levels reaching 49 feet above sea level
A magnitude-8.1 earthquake triggered two major quakes of magnitude 7.8 within two minutes, revealing a unprecedented pattern in the Samoa-Tonga region. The study suggests that normal fault earthquakes can trigger subduction zone quakes, affecting tsunami hazard calculations globally.
Scientists discovered a rare 'triggered doublet' event where two great earthquakes occurred seconds apart on different faults. The initial earthquake triggered another massive event with a total magnitude of 8.0, causing devastating tsunamis that killed 192 people.
Researchers at Monash University and Scripps Institution of Oceanography developed a new mathematical scaling theory to explain the global motions of tectonic plates. The theory demonstrates that the velocities of plates and boundaries depend on subduction zone size and presence of subduction zone edges.
Researchers have discovered that the Indian continental crust was forced down to a depth of at least 200 km under the Asian plate during the Himalayan collision. This finding is significant as it contradicts previous estimates and challenges fundamental parameters of Himalayan tectonics.
New analysis by Oregon State University scientists suggests a high probability of a magnitude 8.2 or higher earthquake in the Cascadia Subduction Zone, with 37% chance in southern segment and 10-15% in northern segment within 50 years. This risk is exacerbated by clusters of major earthquakes occurring every 250 years.
The city of Cannon Beach is building a 9,800-square-foot structure designed to withstand earthquakes and tsunamis, with a cost of $4 million. The structure could shelter up to 1,500 people and serve as a model for other cities affected by tsunamis.
A team of scientists discovered that seismic slip on the Central Peru Megathrust is caused by a combination of earthquakes and non-seismic creep. This finding indicates that movement along this subduction zone is more complex than previously thought.
Scientists discovered that aseismic slip in the Nazca tectonic plate can prevent earthquakes from propagating through certain areas. By analyzing GPS data and aftershock patterns, researchers found a 'patchwork' pattern of aseismicity, with some areas always slipping slowly and others rarely experiencing seismic activity.
This study examines the correlation between end-Triassic mass extinction and flood basalt volcanism, as well as the effects of water depth on pumice formation in submarine domes. It also investigates the relationship between climatic conditions and soil erosion during the last glacial cycle.
Researchers investigate the seismic potential of the Cascadia subduction zone, exploring temporal clustering of earthquakes and the likelihood of a next event by 2060. They also examine slow slip phenomena and landslides, shedding light on precursory patterns that may save lives.
Researchers studied mineralized microfossils, sea level rise, and mammalian fossils to better understand Earth's history. They also found evidence against the Lilliput Effect and geochemical mapping of Mars.
A recent study published in BSSA found that certain types of subduction zones exhibit lower earthquake production rates, contradicting previous assumptions. The research suggests that the efficiency of earthquake production is influenced by fault slip rate and relative plate velocity.
The January-February 2010 GSA Bulletin features studies on the kinematic evolution of curved mountain belts, including a paleomagnetic study of the Sevier thrust belt. The issue also covers the Sudbury impact crater in Michigan, USA, and GIS assessments of post-fire debris-flow hazards in central Idaho.
Yumei Wang, a geotechnical engineer, proposes tsunami evacuation buildings in the Pacific Northwest to mitigate the risk of massive tsunamis. The buildings would provide safe spaces for emergency response and long-term recovery, with estimated costs ranging from $1 million to $2 million.
Expedition 322 collected sedimentary and basement rock samples from the Shikoku Basin, shedding light on the generation of large earthquakes. The study of petrological, geotechnical, frictional, and hydrogeological properties of these rocks is crucial for understanding rupture dynamics in the seismogenic zone.
Recent studies uncover new insights into the Miocene structural reorganization of the South Tibetan detachment, eastern Himalaya, and its implications for understanding continental collision. Additionally, researchers have developed a one-dimensional modeling approach to quantify dip and velocity of continental subduction from high-pre...
Researchers track the pattern and timing of a new subduction zone's birth in Fiordland, New Zealand, and analyze eclogites carried to the surface via serpentinite channels. The study also investigates the Yukon-Tanana terrane's crustal growth, finding predominantly crustal recycling with minor juvenile crustal growth.
Researchers at Oregon State University have created a global three-dimensional map of electrical conductivity in the Earth's mantle, indicating areas of high conductivity coincide with subduction zones. The model suggests that water drawn downward during subduction processes may be responsible for enhanced conductivity in these areas.
Researchers used magnetotelluric sounding to detect large amounts of water in New Zealand's crust, revealing three processes that help deform the crust above it. The study found water is released at varying depths, contributing to earthquake generation and faulting in the region.
New research on jade found in Guatemala's Motagua fault reveals two collision events between the North American and Caribbean plates. The study uses eclogite dating to pinpoint a 130 million-year-old collision, followed by a second event at 70 million years ago.
A new study evaluates expected ground motion in Seattle, Victoria, and Vancouver from earthquakes of magnitude 7.5 - 9.0, providing a tool to build or retrofit structures to withstand seismic waves. Ground motions are estimated for firm ground at the three sites, with a model that engineers can adjust for local soil conditions.
Chevron-shaped dunes are not indicative of mega-tsunamis, contrary to popular speculation. Microbial life extends fossil record by 1.5 billion years, while nanoscale cristobalite fibers in volcanic ash hint at adverse health effects. The largest trilobites ever found provide insight into Earth's first animals and fossil evidence.
A giant Cascadian earthquake could cause severe damage and possible collapse in Seattle's high-rise buildings, particularly those constructed before 1994 building code changes. The Seattle basin amplifies long-period motions, making tall steel buildings susceptible to low-frequency shaking.