Article
Environmental Sciences
Xiaoran Lv, Yun Shao
Summary: Time-series observations from Sentinel-1 A/B InSAR were used to study the late post-seismic deformation velocity field caused by the Kokoxili earthquake. The simulation of deformation velocity and comparison with observed data revealed continuity in the viscoelastic relaxation. The rheological structure of the Kokoxili region was explored through a mixed model, and the estimated viscosities for the lower crust and upper mantle were obtained. The results showed that the viscoelastic layer beneath the Kokoxili regions has almost reached their stable state.
Article
Geochemistry & Geophysics
Caroline Chalumeau, Hans Agurto-Detzel, Louis De Barros, Philippe Charvis, Audrey Galve, Andreas Rietbrock, Alexandra Alvarado, Stephen Hernandez, Susan Beck, Yvonne Font, Mariah C. Hoskins, Sergio Leon-Rios, Anne Meltzer, Colton Lynner, Frederique Rolandone, Jean-Mathieu Nocquet, Marc Regnier, Mario Ruiz, Lillian Soto-Cordero, Sandro Vaca, Monica Segovia
Summary: This study on repeating earthquakes following the Pedernales earthquake in Ecuador found that they occur primarily on the edges of large aftershock clusters and show a pattern of increasing recurrence times over time. The behavior of repeaters may be influenced by stress accumulation at the edge of afterslip and they are more spatially correlated with afterslip gradients.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Hongyu Zeng, Shengji Wei, Ares Rosakis
Summary: This study investigates the impact of source-side 3D velocity structure on teleseismic travel-time in back projection analysis of large earthquakes. Travel-time data recorded by the Hi-Net array is used to reveal how travel-time errors vary with source location. The study proposes a new interpolation scheme to calibrate the travel-time error by using earthquakes located around the mainshock rupture, and validates it through relocating inland M > 5.0 earthquakes in central Japan. The calibrated back projection result is then applied to image the rupture of the 2002 Denali earthquake, revealing useful information about the rupture process.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geosciences, Multidisciplinary
Gege Hui, Pengcheng Wang, Chuang Sun, Yipeng Zhang, Litian Hu
Summary: This study investigates the formation mechanisms of the Mw7.9 Kodiak earthquake in the Gulf of Alaska region through detailed structural analysis and regional crustal stress evaluation using seismology methods. The earthquake sparked debate due to intraplate deformation, complex rupture system near the Aleutian subduction zone, and highly fractured crustal stress status identified at different depths. The research suggests that mantle peridotite serpentinization and reactivation of deep-seated oceanic fracture zones may have contributed to the complex earthquake ruptures in the area.
GEOLOGICAL JOURNAL
(2021)
Article
Geochemistry & Geophysics
Makrem Harzali, Emna Medhioub, Mohamed Mansour Abdelmalak, Abdelkader Hamdouni, Habib Troudi
Summary: On February 6, 2023, a magnitude 7.8 earthquake occurred in the Kahramanmaras region, causing significant casualties. The study revealed that the region is predominantly characterized by strike-slip tectonic regime, with complex fault geometry. The neotectonic activity in the region aligns well with the collision models between the Arabian and Eurasian plates. A detailed seismic hazard assessment is required for the area.
ACTA GEODAETICA ET GEOPHYSICA
(2023)
Article
Geochemistry & Geophysics
Luyuan Huang, Tao Tao, Rui Gao, Yaolin Shi
Summary: Most major earthquakes in Alaska are caused by rupture of the mega-thrust along the Alaska-Aleutian subduction zone. However, rare intraplate earthquakes may also occur in the region. Researchers used a viscoelastic finite-element-method model to calculate time-dependent stress transfer associated with the 1964 Alaska earthquake. They discovered differences in rheological properties between the continental mantle and oceanic mantle using postseismic Global Positioning System measurements.
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2022)
Article
Multidisciplinary Sciences
Zachary E. Ross, Daniel T. Trugman, Egill Hauksson, Peter M. Shearer
Article
Geochemistry & Geophysics
Peter M. Shearer, Rachel E. Abercrombie, Daniel T. Trugman, Wei Wang
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2019)
Article
Geology
Vera Schulte-Pelkum, Gaspar Monsalve, Anne F. Sheehan, Peter Shearer, Francis Wu, Sudhir Rajaure
Article
Geochemistry & Geophysics
Peter M. Shearer, Janine Buehler
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2019)
Article
Geosciences, Multidisciplinary
Wenyuan Fan, Jeffrey J. McGuire, Peter M. Shearer
GEOPHYSICAL RESEARCH LETTERS
(2020)
Article
Multidisciplinary Sciences
Songqiao Shawn Wei, Peter M. Shearer, Carolina Lithgow-Bertelloni, Lars Stixrude, Dongdong Tian
Article
Astronomy & Astrophysics
Robin S. Matoza, Paul G. Okubo, Peter M. Shearer
Summary: A high-precision catalog of relocated seismicity from 1986 to 2018 reveals concentrated seismic activity along faults, streaks, rings, magma pathways, etc., providing a clearer picture of crustal detachments on the flanks of Kilauea and Mauna Loa.
EARTH AND SPACE SCIENCE
(2021)
Article
Geochemistry & Geophysics
Peter M. Shearer, Rachel E. Abercrombie
Summary: Empirical approaches are commonly used to correct earthquake spectra, but suffer from tradeoffs among source parameters and correction terms, limiting absolute stress-drop estimates. Borehole records provide more direct constraints on source spectra compared to surface seismometers. Purely empirical methods for spectral analysis may have limitations, highlighting the importance of determining crustal attenuation models.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Tianze Liu, Peter M. Shearer
Summary: A new method using S-reflections generated by teleseismic S waves is proposed to image lithospheric discontinuities, providing high-resolution images of LAB and MLD below the contiguous US. The results show reasonable agreement with traditional techniques, suggesting the possibility of joint inversion for better constraint of lithospheric discontinuity properties.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geosciences, Multidisciplinary
Guoqing Lin, Peter M. Shearer
Summary: This study investigates the changes in earthquake faulting geometry and the P-wave to S-wave speed ratio in relation to the 2018 Kilauea volcano eruption. Changes in earthquake fault orientations were observed in both the summit area and the central south flank as early as December 2017, indicating internal forces within the volcano had shifted months before the eruption. The ratios of P to S wave speed were also found to change corresponding to the eruption, with very low ratios beneath the summit and the Lower East Rift Zone, suggesting movement of volatiles. Seismic parameters can be highly sensitive to volcanic activities and provide valuable insight into the evolution of volcanic and tectonic activity.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Tianze Liu, Peter M. Shearer
Summary: Seismic noise, including both surface waves and body waves, has been widely used for imaging Earth's structure. This study focuses on identifying and analyzing body-wave noise, specifically PKP waves, using array analyses. The results suggest that the phase differential between PKS and PKP can potentially be used for shear-wave-splitting analysis. Additionally, the study highlights the heterogeneous nature of sources for body-wave noise in both space and time, which should be taken into account in future studies.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Peter M. Shearer, Rachel E. Abercrombie, Daniel T. Trugman
Summary: We estimated Brune-type stress drops for over 70,000 M 1.5-4 earthquakes in southern California from 1996 to 2019 using a P-wave spectral decomposition approach. Our findings reveal spatial variations in stress drops and suggest a potential increase in stress drop with moment for M 3-4 earthquakes.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
Peter M. M. Shearer, Haoran Meng, Wenyuan Fan
Summary: We have successfully detected thousands of small earthquakes near an active strand of the San Jacinto fault zone in southern California using a dense seismic array. By correcting site effects and performing beamforming analysis, we have identified 13,408 events, including a significant number that were not cataloged before. These detections exhibit distinct characteristics and patterns, such as clusters associated with known earthquake locations and a Gutenberg-Richter distribution of amplitudes. The presence of foreshocks and their rate increase before mainshocks also follows an inverse Omori's law.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Shangqin Hao, Peter Shearer, Tianze Liu
Summary: By combining data from the EarthScope Transportable Array and other regional seismic networks, we obtained a high-resolution map of the Moho and upper-mantle discontinuities beneath Alaska. The crustal thickness is correlated with elevation and the deepest Moho is found in the basal accretion region of the subducted Yakutat plate. We also resolved the 410, 520, and 660 discontinuities in most regions, indicating the presence of the subducted Pacific slab in the upper mantle transition zone.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Multidisciplinary Sciences
Zhe Jia, Zeyu Jin, Mathilde Marchandon, Thomas Ulrich, Alice-Agnes Gabriel, Wenyuan Fan, Peter Shearer, Xiaoyu Zou, John Rekoske, Fatih Bulut, Asli Garagon, Yuri Fialko
Summary: This study integrates multiscale seismic and space-geodetic observations with multifault kinematic inversions and dynamic rupture modeling to unravel the complex rupture history and stress-mediated fault interactions of the doublet earthquake event in Turkey in 2023. The results highlight the importance of combining near- and far-field observations with data-driven and physics-based models for seismic hazard assessment.