Phys.org March 3, 2023 The movement and deformation of the Earth’s crust and upper mantle provide critical insights into the evolution of earthquake processes and future earthquake potentials. Crustal deformation can be modeled by dislocation models that represent earthquake faults in the crust as defects in a continuum medium. Researchers in Japan have proposed a physics-informed deep learning approach to model crustal deformation due to earthquakes. Neural networks can represent continuous displacement fields in arbitrary geometrical structures and mechanical properties of rocks by incorporating governing equations and boundary conditions into a loss function. They introduced polar coordinate system to accurately […]
Category Archives: Earthquakes
California Quakes Mysteriously Preceded by Shifts in Earth’s Magnetic Field
Science Alert October 10, 2022 Magnetic field changes as earthquake precursors have been the subject of numerous studies and some controversy. Infrequent large earthquakes and sparse magnetometer coverage along fault zones complicate statistical analysis. A team of researchers in the US (Google Research, industry) analyzed ground-based magnetic time-series measurements before 19 earthquakes in California drawing from over 330,000 site-days of measurement spanning a decade. They applied a pre-specified statistical analysis with two key ideas – combining signals from nearby sites via spectral cross-power, and then looking for large spikes in frequency domain 0.016–25 Hz. They used the machine learning concept […]
Months of gravity changes preceded the Tōhoku earthquake
Phys.org September 1, 2022 Researchers in France conducted a global analysis of Gravity Recovery and Climate Experiment (GRACE) reconstructed gravity gradients from July 2004 to February 2011 to test whether the deep signals preceding the March 2011 Tohoku earthquake could be detected before the event as a specific feature originating from solid Earth. They improved the angular resolution of the gravity gradients using two overlapping ranges of azimuthal sensitivity to investigate short-term signals of large amplitude aligned with the orientation of the Northwestern Pacific subduction and set-up a method to identify consistent solid Earth signals shared by different GRACE gravity […]
Hidden magnitude-8.2 earthquake source of mysterious 2021 global tsunami
Phys.org February 8, 2022 The 2021 August South Sandwich Island Mw 8.2 earthquake was a surprise, because it was initially reported as a magnitude 7.5 event at a deep depth (47 km) but generated a global-spreading tsunami that would only be expected for a larger and shallower event. By using seismic data researchers at Caltech revealed a hidden Mw 8.16 shallow slow event that happened between clusters of regular ruptures in the beginning and end. Although the slow event contributed 70% of the seismic moment, lasted three minutes, and ruptured a 200-km section of the plate interface, it is essentially […]
New type of earthquake discovered
Phys.org December 6, 2021 A seismic slip loading has recently been proposed as a complementary mechanism to induce moderate-sized earthquakes located within a few kilometers of the wellbore over the timescales of hydraulic stimulation. However, aseismic slip signals linked to injection-induced earthquakes remain largely undocumented to date. An international team of researchers (Canada, Germany) has reported a new type of earthquake characterized by hybrid-frequency waveforms (EHWs). Distinguishing features from typical induced earthquakes include broader P and S-pulses and relatively lower-frequency coda content. Both features may be causally related to lower corner frequencies, implying longer source durations, thus, either slower rupture […]
Keeping one step ahead of earthquakes
Phys.org November 3, 2021 According to the researchers in France AI has the potential to improve the accuracy and speed of early warning systems. Earthquake early warning (EEW) systems are evolving rapidly due to advances in computer power and network communication. They work by identifying the first signals generated by an earthquake rupture before the strongest shaking and tsunami reach populated areas. These signals follow the origin of the earthquake and can be recorded seconds before the seismic waves. Prompt elasto-gravity signal (PEGS) which was recently identified travels at the speed of light but is a million times smaller than […]
Anatomy of an earthquake series
Science Daily August 11, 2021 Gas storage oil field operations worldwide are typically not stimulating substantial seismicity. However, the Castor sequence in Spain remains to date the most significant case of seismicity related to this type of industrial operations in Europe. The new analysis by an international team of researchers (Germany, Spain, Italy, Switzerland, USA- Stanford University) identified about 3,500 earthquakes, which took place at shallow depth between September and early October in the vicinity of the Castor injection platform using a combination of advanced seismological techniques applied to an enhanced waveform dataset to better understand the seismogenic process and […]
Minor volcanic eruptions could ‘cascade’ into global catastrophe
Science Daily August 6, 2021 The typical focus of attention for global-scale catastrophes has been on large-scale eruptions with a volcanic explosivity index (VEI) of 7–8. An international team of researchers (UK, Israel) has identified seven “pinch points” where clusters of relatively small but active volcanoes sit alongside vital infrastructure that, if paralyzed, could have catastrophic global consequences. They include, the volcanic group on the northern tip of Taiwan, the home to one of the largest producers of electronic chips; The Mediterranean, where earthquakes can induce tsunamis that smash submerged cable networks and seal off the Suez Canal; eruptions in […]
Weird Electromagnetic Bursts Appear Before Earthquakes – And We May Finally Know Why
Science Alert May 30, 2021 Seismologists have been aware of brief, subtle anomalies in underground electrical fields leading up to an earthquake, sometimes occurring as soon as a few weeks before the quake happens. Research suggests that when gases interact with newly created crack surfaces, the unpaired electrons within the rock crystal defects are thermally stimulated, released into the crack due to the temperature rise at the crack tip via plastic work, and attached to ambient gas molecules to electrify them in a negative state. Researchers in Japan used a customized lab setup to test the reactions of quartz diorite, […]
Research finds quakes can systematically trigger other ones on opposite side of Earth
Oregon State University August 1, 2018 Researchers at Oregon State University analyzed seismic data from 1973 through 2016, excluding data from aftershock zones, using larger time windows than in previous studies. A tremblor is most likely to induce another quake within 30 degrees of the original quake’s antipode – the point directly opposite it on the other side of the globe. The understanding of the mechanics of how one earthquake could initiate another while being widely separated in distance and time is still largely speculative. But irrespective of the specific mechanics involved, evidence shows that triggering does take place, followed […]