Article
Geochemistry & Geophysics
Yijun Zhang, Han Bao, Yosuke Aoki, Akinori Hashima
Summary: We constructed an integrated rupture model of the 2021 M-w 7.1 Fukushima earthquake and analyzed its kinematic rupture, slip distribution, and stress changes. The study found that the rupture propagated along both the strike and dip directions, with a large-slip area located southwest to the hypocentre. The temporal change of stress suggested that the occurrence of the Fukushima earthquake may have been promoted by the post-seismic deformation due to the 2011 Tohoku-Oki earthquake.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Malcolm C. A. White, Hongjian Fang, Rufus D. Catchings, Mark R. Goldman, Jamison H. Steidl, Yehuda Ben-Zion
Summary: This study presents a detailed earthquake catalogue and velocity models for the 2019 Ridgecrest, California, earthquake sequence, derived using data recorded by densely deployed sensors following the main shock. The models correlate well with surface geology and seismicity patterns, providing insights into the seismic behavior in the region.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
P. Papadimitriou, V Kapetanidis, A. Karakonstantis, I Spingos, K. Pavlou, G. Kaviris, I Kassaras, V Sakkas, N. Voulgaris
Summary: The characteristics of the M-w = 6.7 earthquake that occurred near Zakynthos Island, Greece in October 2018 were thoroughly examined, revealing strong spatial clustering of aftershocks in the northern and southern regions, potentially related to plate tectonics.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
D. Legrand, A. Iglesias, S. K. Singh, V Cruz-Atienza, C. Yoon, L. A. Dominguez, R. W. Valenzuela, G. Suarez, O. Castro-Artola
Summary: The rate of aftershocks is high in the Ometepec segment of the Mexican subduction zone, likely due to the presence of overpressured fluids and a rough plate interface. This is characterized by a high b-value and slow decaying aftershock sequence.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Michael Gunnels, Gurban Yetrimishli, Sabina Kazimova, Eric Sandvol
Summary: Through high-resolution 3-D seismic velocity models and a relocated earthquake catalogue, we observed the seismic activity and velocity structure characteristics in Azerbaijan. The seismic hypocenters cluster into two depth ranges, with intermediate depth seismicity beneath the Kura Basin. Significant variation in seismic velocities was also noted, with the structure of the Kura Basin reflecting that of the Caspian Sea, suggesting a continuation of the Caspian geodynamics into Azerbaijan.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Can Oren, Jeffrey Shragge
Summary: The study proposes a methodology for microseismic image-domain wavefield tomography using the elastic wave equation and zero-lag and extended source images to improve the accuracy of elastic velocity models and event location precision.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Carlos Herrera, Francisco Pasten-Araya, Leoncio Cabrera, Bertrand Potin, Efrain Rivera, Sergio Ruiz, Raul Madariaga, Eduardo Contreras-Reyes
Summary: This study investigates the 2020 Calama earthquake sequence and compares it with other significant earthquakes in the area. The results show that the Calama main shock has similar stress drop and dynamic rupture parameters as the nearby Michilla and Jujuy earthquakes. The Calama sequence occurred in the upper lithospheric mantle with lower aftershock productivity and a less hydrated environment.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Guoqing Lin, Zhigang Peng, Miguel Neves
Summary: This study presents estimations and comparisons of in situ V-p/V-s ratios and seismicity characteristics for the Parkfield segment of the San Andreas fault in northern California and the San Jacinto Fault Zone and its adjacent regions in southern California. The high-resolution in situ V-p/V-s ratios are found to be more complex than the tomographic V-p/V-s models and are influenced by material properties and fluid contents. The study also observes velocity contrasts between different fault sections and anomalous V-p/V-s variation patterns in southern California. The correlation between similar events and anomalous V-p/V-s ratios supports the role of fluids in repeating earthquakes.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Kodai Sagae, Hisashi Nakahara, Takeshi Nishimura, Kazutoshi Imanishi
Summary: This study detected and located deep low-frequency tremors beneath the Kii Peninsula, Nankai subduction zone, Japan, using data from a dense seismic array. The high-resolution tremor catalogue revealed various characteristics of tremor activity, including continuous updip migration and different migration speeds depending on along-strike migration. The results also suggest a depth dependence of frictional strength on the plate interface and a positive correlation between accumulated radiated energies and updip migration speed, implying a potential role of fluid migration in the updip migration process.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Dong Yan, You Tian, Dapeng Zhao, Hongli Li
Summary: A high-precision earthquake catalog was created using continuous waveform data recorded at 360 portable seismographs deployed in the Changbaishan-Tianchi volcanic area. The study revealed the 3-D structures of the crust beneath the study region and identified a high-Vp/Vs zone accompanied by volcanic earthquakes, indicating the presence of a magma chamber. The findings suggest a multilevel structure of magma chambers in the upper and middle crust, which is closely associated with the diverse eruption styles of the Changbaishan volcano.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Koichiro Obana, Gou Fujie, Yojiro Yamamoto, Yuka Kaiho, Yasuyuki Nakamura, Seiichi Miura, Shuichi Kodaira
Summary: The study investigated aftershock activities in the southern Japan Trench and found linear earthquake trends parallel and oblique to the trench axis. In the trench landward area, earthquake activity showed variations along the trench, with shallow near-trench regular earthquakes observed near the trench axis. The study also suggested that smaller spatial scale structure heterogeneity could relate to the diversity of slip behaviors in the shallow subduction zone.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Jaewoo Kim, YoungHee Kim
Summary: By using seismic anisotropy from shear wave splitting, we studied the pore fluid characteristics of the Groningen gas field in the Netherlands. Through analysis of 663 high-quality splitting parameters obtained from induced earthquakes, we found that crustal anisotropy in Groningen is closely related to fluid flow changes and reservoir compaction. The results show that anisotropy strength is lower near shut-in wells with significant compaction, while higher anisotropy strength is observed near operating wells with less compaction. Temporal variations also differ between shut-in and production wells.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Elena Eva, Franco Pettenati, Stefano Solarino, Livio Sirovich
Summary: By analyzing detailed seismic data, it was confirmed that the seismogenic source of the 1920 earthquake was the Compione-Comano fault located on the NE edge of the Lunigiana graben. This study provides valuable insights for hazard assessment and seismotectonic research.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Yojiro Yamamoto, Dogan Kalafat, Ali Pinar, Narumi Takahashi, Remzi Polat, Yoshiyuki Kaneda, Haluk Ozener
Summary: The study used ocean bottom seismometer observations to assess the location of possible asperities for future large earthquakes, finding that offshore observations are more accurate and can detect more microearthquakes compared to land-based observations. Results from 2014 to 2017 show that the seismic activity pattern along the North Anatolian Fault beneath the Marmara Sea has remained unchanged.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geosciences, Multidisciplinary
F. Napolitano, O. Amoroso, V. De Novellis, G. M. Adinolfi, R. De Matteis, E. Sansosti, D. Russo, R. Caputo, V. Convertito
Summary: We used 3D seismic tomography to image the crustal volume affected by the March-April 2021 Thessaly sequence. The results reveal blind fluid-filled inherited structures and a basal detachment accommodating the Pelagonian nappe onto the carbonate of the Gavrovo unit. The high V-P/V-S ratios in the northwest edge of the seismogenic volume suggest possible fluid accumulation that contributed to the evolution of the sequence, and additional faults parallel and antithetical to the main structures were identified for future seismic risk mitigation.
FRONTIERS IN EARTH SCIENCE
(2023)