Preprints
Search for earthquake (504 results)
Modelling high-frequency seismograms at ocean bottom seismometers: effects of heterogeneous structures on source parameter estimation for small offshore earthquakes and shallow low-frequency tremors
Published: 2020-04-18
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The source characteristics of offshore seismic events, especially regular (or fast) and slow earthquakes, can provide key information on their source physics and frictional conditions at the plate boundary. Due to strong three-dimensional heterogeneities in offshore regions, such as those relating to seawater, accretionary prism, and small-scale velocity heterogeneity, conventional methods using [...]
Lateral variations in lower crustal strength control the temporal evolution of mountain ranges: examples from south-east Tibet
Published: 2020-04-17
Subjects: Earth Sciences, Geochemistry, Geomorphology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Controversy surrounds the rheology of the continental lithosphere, and how it controls the evolution and behaviour of mountain ranges. In this study, we investigate the effect of lateral contrasts in the strength of the lower crust, such as those between cratonic continental interiors and weaker rocks in the adjacent deforming regions, on the evolution of topography. We combine numerical [...]
Forming a Mogi Doughnut in the years prior to and immediately before the the 2014 M8.1 Iquique, Northern Chile Earthquake
Published: 2020-04-15
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Asperities are patches where the fault surfaces stick until they break in earthquakes. Locating asperities and understanding their causes in subduction zones is challenging because they are generally located offshore. We use seismicity, inter- and co-seismic slip, and the residual gravity field to map the asperity responsible for the 2014 M8.1 Iquique Chile earthquake. Until two weeks before the [...]
Interferometric Processing of ScanSAR Data Using Stripmap Processor: New Insights from Coregistration
Published: 2020-04-14
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Computer Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Geology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Processing scanning synthetic aperture radar (ScanSAR) data using a stripmap processor, which is called full-aperture processing, has been the choice of many researchers. ScanSAR data are known to require very high azimuth coregistration precision which is usually achieved by a geometrical coregistration followed by a spectral diversity coregistration on the ScanSAR burst. However, for [...]
Interferometry with ALOS-2 full-aperture ScanSAR data
Published: 2020-04-14
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Geology, Geophysics and Seismology, Glaciology, Mining Engineering, Other Engineering, Physical Sciences and Mathematics, Physics, Tectonics and Structure, Volcanology
Advanced Land Observing Satellite-2 (ALOS-2) is designed to routinely acquire both scanning synthetic aperture radar (ScanSAR) and stripmap data. In this paper, we present a special multiband bandpass filter (MBF) to remove azimuth nonoverlap spectra for the interferometric processing of ALOS-2 full-aperture ScanSAR product. As required by the MBF, we estimate the important ScanSAR system [...]
Aquifer deformation and active faulting in Salt Lake Valley, Utah, USA
Published: 2020-04-12
Subjects: Earth Sciences, Geophysics and Seismology, Hydrology, Physical Sciences and Mathematics
Aquifers and fault zones may interact through groundwater flow and stress redistribution, yet their spatiotemporal relationship remains enigmatic. Here we quantify changes in water storage and associated stress along the Wasatch Fault Zone in Salt Lake Valley, recently shaken by a M5.7 earthquake on March 18th, 2020. Ground deformation mapped by Sentinel-1 SAR imagery (2014-2019) reveals an [...]
InSAR Time Series Analysis of L-band Wide- Swath SAR Data Acquired by ALOS-2
Published: 2020-04-12
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Environmental Sciences, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Operating at L-band (~24 cm wavelength) in wide-swath modes is one of the characteristics of the new and next generation satellite synthetic aperture radar (SAR) missions. After 3 years of operation, the Japan Aerospace Exploration Agency Advanced Land Observing Satellite-2 (ALOS-2) satellite has acquired a wealth of L-band wide-swath SAR data over many areas using its ScanSAR mode. We present [...]
Seismic electric signals (SES) and earthquakes: A review of an updated VAN method and competing hypotheses for SES generation and earthquake triggering
Published: 2020-04-07
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Studies, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Planetary Geophysics and Seismology, Planetary Sciences, Social and Behavioral Sciences
Electromagnetic phenomena are sometimes associated with seismic events, but earthquake prediction using seismic electric signals (SES) has not been seriously considered since the early 1990s. There are several causes: (1) false alarms that have created panics in Greece, and (2) a strong critique of the Varotsos-Alexopoulos-Nomicos (VAN) method used there. An updated VAN method that includes time [...]
Is the Aftershock Zone Area a Good Proxy for the Mainshock Rupture Area?
Published: 2020-04-07
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The locations of aftershocks are often observed to be on the same fault plane as the mainshock and used as proxies for its rupture area. Recent developments in earthquake relocation techniques have led to great improvements in the accuracy of earthquake locations, offering an unprecedented opportunity to quantify both the aftershock distribution and mainshock rupture area. In this study, we [...]
Measuring Azimuth Deformation With L-Band ALOS-2 ScanSAR Interferometry
Published: 2020-04-06
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Computational Engineering, Computer Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Signal Processing, Tectonics and Structure, Volcanology
We analyze the methods for measuring azimuth deformation with the L-band Advanced Land Observing Satellite-2 (ALOS-2) scanning synthetic aperture radar (ScanSAR) interferometry. To implement the methods, we extract focused bursts from the ALOS-2 full-aperture product, which is the only product available for ScanSAR interferometry at present. The extracted bursts are properly processed to measure [...]
Estimating Azimuth Offset With Double-Difference Interferometric Phase: The Effect of Azimuth FM Rate Error in Focusing
Published: 2020-04-06
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Environmental Sciences, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Physics, Tectonics and Structure, Volcanology
Estimating azimuth offset with double-difference interferometric (DDI) phase, which is called multiple-aperture interferometric synthetic aperture radar (InSAR) or spectral diversity, is increasingly used in recent years to measure azimuth deformation or to accurately coregister a pair of InSAR images. We analyze the effect of frequency modulation (FM) rate error in focusing on the DDI phase with [...]
Continuum of earthquake rupture speeds enabled by oblique slip
Published: 2020-03-31
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Earthquake rupture speed can affect ground shaking and thus seismic hazard. Seismological observations show that large earthquakes span a continuum of rupture speeds, from slower than Rayleigh waves up to P wave speed, and include speeds that are predicted to be unstable by 2D theory. This discrepancy between observations and theory has not yet been reconciled by a quantitative model. Here we [...]
Rupture Kinematics of January 24, 2020 Mw 6.7 Doğanyol-Sivrice, Turkey Earthquake on the East Anatolian Fault Zone Imaged by Space Geodesy
Published: 2020-03-19
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Here we present the results of a kinematic slip model of the 2020 Mw 6.7 Doğanyol-Sivrice, Turkey Earthquake, the most important event in the last 50 years on the East Anatolian Fault zone. Our slip model is constrained by two Sentinel-1 interferograms and by 5 three-component high-rate GNSS recordings close to the earthquake source. We find that most of the slip occurs predominantly in three [...]
Space-time stress variations on the Palu-Koro fault impacting the 2018 Mw 7.5 Palu earthquake and its seismic hazards
Published: 2020-03-09
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
In this study we calculated the Coulomb stress change before and after the 2018 Palu earthquake (Mw7.5) induced by historical large earthquakes on and around the Palu‐Koro fault (PKF) within Sulawesi Island, Indonesia. We found that the 1996 earthquake (Mw7.9) on the Minahassa thrust likely promoted the 2018 Palu earthquake by stress loading on its hypocenter. Stress shadows in the PKF impacted [...]
Improving the retrieval of offshore-onshore correlation functions with machine learning
Published: 2020-03-06
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The retrieval of reliable offshore-onshore correlation functions is critical to improve our ability to predict long-period ground motions from megathrust earthquakes. However, localized ambient seismic field sources between offshore and onshore stations can bias correlation functions and generate non-physical arrivals. We present a two-step method based on unsupervised learning to improve the [...]