5 results on '"Song, Chuang"'
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2. Two M w ≥ 6.5 Earthquakes in Central Pamir Constrained by Satellite SAR Observations.
- Author
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Wang, Shuai, Song, Chuang, and Xiao, Zhuohui
- Subjects
- *
SYNTHETIC aperture radar , *EARTHQUAKES , *SHEAR zones - Abstract
The Pamir, situated in central Asia, is a result of the ongoing northward advance of the Indian continent, leading to compression of the Asian landmass. While geodetic and seismic data typically indicate that the most significant deformation in Pamir is along its northern boundary, an Mw 7.2 earthquake on 7 December 2015 and an Mw 6.8 earthquake on 23 February 2023 have occurred in the remote interior of Pamir. These two Mw ≥ 6.5 earthquakes, with good observations of satellite synthetic aperture radar data, provide a rare opportunity to gain insights into rupture mechanics and deformation patterns in this challenging-to-reach region. Here, we utilize spaceborne synthetic aperture radar data to determine the seismogenic faults and finite slip models for these two earthquakes. Our results reveal that the 2015 earthquake ruptured a ~88 km long, left-lateral strike-slip fault that dips to northwest. The rupture of the 2015 earthquake extended to the ground surface over a length of ~50 km with a maximum slip of ~3.5 m. In contrast, the 2023 earthquake did not rupture the ground surface, with a maximum slip of ~2.2 m estimated at a depth of ~9 km. Notably, the seismogenic fault of the 2015 earthquake does not align with the primary strand of the Sarez–Karakul fault system (SKFS), and the 2023 earthquake occurred on a previously unmapped fault. The well-determined seismogenic faults for the 2015 and 2023 earthquakes, along with the SKFS and other distributed faults in the region, suggest the existence of a wide shear zone extending from south to north within the central Pamir. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Geodetic Constraints on Recent Subduction Earthquakes and Future Seismic Hazards in the Southwestern Coast of Mexico.
- Author
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Yu, Chen, Li, Zhenhong, and Song, Chuang
- Subjects
TSUNAMI warning systems ,EARTHQUAKE hazard analysis ,SUBDUCTION ,SEISMOGRAMS ,GEODETIC satellites ,DISPLACEMENT (Mechanics) ,EARTHQUAKE damage - Abstract
Three major subduction earthquakes occurred on March 20, 2012 (Mw 7.4), February 16, 2018 (Mw 7.2), and June 23, 2020 (Mw 7.4) in the southwestern coast of Mexico, which caused fatalities, casualties, considerable damage, and raised safety concerns about future seismic hazards. We use satellite geodetic observations to invert for the slip distributions of the three events and then investigate their interactions. Coulomb Failure Stress (CFS) induced by their slip both on surrounding thrust and normal faults are calculated. The positive CFS changes, along with the spatial‐temporal seismicity evolution, approximate earthquake recurrence rate and interseismic coupling, collectively indicate an increased possibility of a near‐future rupture around the areas between the 2018 and 2020 events in Oaxaca. Furthermore, there is a lowered chance of shallow coastal or offshore normal earthquakes but an increased chance of inland normal ruptures. Plain Language Summary: Large earthquakes result in stress changes, which can induce or retard regional seismic activity or even trigger other earthquakes. Therefore, understanding historical and recent earthquakes and their associated stress changes are crucial in the evaluation of future seismic hazards. One of the most popular and intuitive ways to relate past and future events is to calculate the Coulomb stress changes during an earthquake and a failure criterion can be established by considering the geometry of nearby faults and the stress changes induced by past events. This requires a detailed knowledge of the amount and direction of slip by which the main fault has slipped during its past ruptures. In this study, we use geodetic surface displacement measurements to invert for the slip distribution and the interactions of three subsequent subduction earthquakes in the southwestern coast of Mexico. We then evaluate the future seismic hazard of the region by considering Coulomb failure stress changes, spatial‐temporal regional seismic activities, historic earthquake records and approximate earthquake recurrence rate. The results show increased chances of a near‐future reverse rupture around Santa Catarina Juquila, Oaxaca and inland normal ruptures, but a lowered chance of shallow coastal or offshore normal ruptures. Key Points: Slip distribution and interactions of three recent subduction earthquakes in Mexico revealed from radar observationsIncreased probability of a near‐future major earthquake around areas between the 2018 and 2020 events in OaxacaLowered chance of shallow coastal or offshore normal earthquakes but increased chance of inland normal ruptures [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
4. Quantifying Ground Subsidence Associated with Aquifer Overexploitation Using Space-Borne Radar Interferometry in Kabul, Afghanistan.
- Author
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Meldebekova, Gauhar, Yu, Chen, Li, Zhenhong, and Song, Chuang
- Subjects
SPACE-based radar ,RADAR interferometry ,LAND subsidence ,HYDROGEOLOGY ,SYNTHETIC aperture radar ,WATER table ,AQUIFERS ,GROUNDWATER - Abstract
Rapid population growth combined with recent drought events and decades of political instability have left the residents of Kabul facing water scarcity, significantly relying on groundwater. Groundwater overexploitation might have induced various magnitudes of ground subsidence, however, to date, no comprehensive study of ground subsidence in Kabul has been conducted. In this study, we investigated the spatio-temporal evolution of ground deformation phenomena and its main governing processes in Kabul from 2014 to 2019 using C-Band Sentinel-1 derived Interferometric Synthetic Aperture Radar (InSAR) time-series from both ascending and descending orbits to extract the two-dimensional (2D) surface displacement field. Four subsidence bowls were distinguished with highly variable spatial extents and deformation magnitudes over four separate aquifer basins, with the maximum value of −5.3 cm/year observed in the Upper Kabul aquifer basin. A wavelet analysis suggests that there is a strong correlation between the groundwater level variations and subsidence. Investigation of hydrogeological data further reveals that the observed subsidence could be attributed to the presence of highly compressible clayey soils. This detailed space-borne regional survey provides new insights into the main governing mechanism of land subsidence in Kabul and may direct better mitigation plans of potential hazards. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
5. Landslide geometry and activity in Villa de la Independencia (Bolivia) revealed by InSAR and seismic noise measurements
- Author
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Chen Yu, Matteo Del Soldato, Chuang Song, Abel Cruz, Stefano Utili, Zhenhong Li, Veronica Pazzi, Song, Chuang, Yu, Chen, Li, Zhenhong, Pazzi, Veronica, Del Soldato, Matteo, Cruz, Abel, and Utili, Stefano
- Subjects
Bolivia ,010504 meteorology & atmospheric sciences ,Compound landslide ,InSAR ,H/V method ,Landslide triggers ,Landslide trigger ,Inverse transform sampling ,Landslide ,Slip (materials science) ,Multiple failure ,Seismic noise ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,Displacement (vector) ,13. Climate action ,Natural hazard ,Interferometric synthetic aperture radar ,Geology ,Seismology ,0105 earth and related environmental sciences - Abstract
Interferometric Synthetic Aperture Radar (InSAR) enables detailed investigation of surface landslide movements, but it cannot provide information about subsurface structures. In this work, InSAR measurements were integrated with seismic noise in situ measurements to analyse both the surface and subsurface characteristics of a complex slow-moving landslide exhibiting multiple failure surfaces. The landslide body involves a town of around 6000 inhabitants, Villa de la Independencia (Bolivia), where extensive damages to buildings have been observed. To investigate the spatial-temporal characteristics of the landslide motion, Sentinel-1 displacement time series from October 2014 to December 2019 were produced. A new geometric inversion method is proposed to determine the best-fit sliding direction and inclination of the landslide. Our results indicate that the landslide is featured by a compound movement where three different blocks slide. This is further evidenced by seismic noise measurements which identified that the different dynamic characteristics of the three sub-blocks were possibly due to the different properties of shallow and deep slip surfaces. Determination of the slip surface depths allows for estimating the overall landslide volume (9.18 · 107 m3). Furthermore, Sentinel-1 time series show that the landslide movements manifest substantial accelerations in early 2018 and 2019, coinciding with increased precipitations in the late rainy season which are identified as the most likely triggers of the observed accelerations. This study showcases the potential of integrating InSAR and seismic noise techniques to understand the landslide mechanism from ground to subsurface.
- Published
- 2021
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