Aspects of earthquake triggering and seismicity clustering /
Earthquakes strongly cluster in space and time, driven both by earthquake-to-earthquake triggering and underlying physical processes, such as tectonic stress loading, increased pore pressure, etc. I explore both global and regional datasets to understand characteristics of these processes in differe...
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ftcdlib:qt8g78688w 2023-05-15T13:32:40+02:00 Aspects of earthquake triggering and seismicity clustering / Chen, Xiaowei 1 PDF (1 online resource xviii, 169 pages) 2013-01-01 application/pdf http://www.escholarship.org/uc/item/8g78688w http://n2t.net/ark:/20775/bb34826387 unknown eScholarship, University of California http://www.escholarship.org/uc/item/8g78688w qt8g78688w http://n2t.net/ark:/20775/bb34826387 public Chen, Xiaowei. (2013). Aspects of earthquake triggering and seismicity clustering /. UC San Diego: Retrieved from: http://www.escholarship.org/uc/item/8g78688w UCSD Dissertations Academic Earth sciences. (Discipline) dissertation 2013 ftcdlib 2016-04-02T19:05:15Z Earthquakes strongly cluster in space and time, driven both by earthquake-to-earthquake triggering and underlying physical processes, such as tectonic stress loading, increased pore pressure, etc. I explore both global and regional datasets to understand characteristics of these processes in different tectonic environments. I study global seismicity using intermediate-period (35--70~s) Rayleigh waves recorded by the global seismic network. Applying a surface wave detect method identifies about 1000 previously un-cataloged earthquakes from 1997 to 2009, most of which are located in the southern ocean. I further analyze a small number of these events that are located in Antarctica to understand glacial-related triggering processes. Absolute and differential travel-times measured from waveform cross-correlation are used to obtain refined locations. A single-force model is applied to the observed amplitudes at 50~Hz to obtain best-fitting force directions. Additionally, possible glacial calving events are identified from MODIS images. The combined results suggest that events on Vanderford and Ninnis glaciers are a result of calving processes. To understand the general characteristics of earthquake clustering from a large dataset of earthquakes, I analyze seismicity in southern California. I use a high-resolution earthquake catalog based on waveform cross-correlation to study the spatial- temporal distribution of earthquakes. Parameters based on event location, magnitude and occurrence time are computed for isolated seismicity clusters. Spatial migration behavior is modeled using a weighted-least-squares method. Aftershock-like event clusters do not exhibit significant spatial migration compared with earthquake swarms. Two triggering processes are considered for swarms: slow slip and fluid diffusion, which are distinguished based on a statistical analysis of event migration. The results suggest fluid-induced seismicity is found across southern California, particularly within geothermal areas. In the Salton Sea geothermal field (SSGF), a correlation between seismicity and fluid injection activities is seen. Spatial -temporal variations of earthquake stress drops are investigated in different regions, and a distance- dependence of stress drop from the injection source is found in the SSGF, suggesting the influence of increased pore pressure. Temporal variation of stress drops within mainshock source regions shows that foreshocks and earthquake swarms have lower stress drops than background seismicity and aftershocks. These results, combined with the spatial migration observed for some large foreshock sequences, suggests an aseismic transient process is likely involved in foreshock triggering Doctoral or Postdoctoral Thesis Antarc* Antarctica Southern Ocean University of California: eScholarship Southern Ocean |
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University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
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UCSD Dissertations Academic Earth sciences. (Discipline) |
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UCSD Dissertations Academic Earth sciences. (Discipline) Chen, Xiaowei Aspects of earthquake triggering and seismicity clustering / |
topic_facet |
UCSD Dissertations Academic Earth sciences. (Discipline) |
description |
Earthquakes strongly cluster in space and time, driven both by earthquake-to-earthquake triggering and underlying physical processes, such as tectonic stress loading, increased pore pressure, etc. I explore both global and regional datasets to understand characteristics of these processes in different tectonic environments. I study global seismicity using intermediate-period (35--70~s) Rayleigh waves recorded by the global seismic network. Applying a surface wave detect method identifies about 1000 previously un-cataloged earthquakes from 1997 to 2009, most of which are located in the southern ocean. I further analyze a small number of these events that are located in Antarctica to understand glacial-related triggering processes. Absolute and differential travel-times measured from waveform cross-correlation are used to obtain refined locations. A single-force model is applied to the observed amplitudes at 50~Hz to obtain best-fitting force directions. Additionally, possible glacial calving events are identified from MODIS images. The combined results suggest that events on Vanderford and Ninnis glaciers are a result of calving processes. To understand the general characteristics of earthquake clustering from a large dataset of earthquakes, I analyze seismicity in southern California. I use a high-resolution earthquake catalog based on waveform cross-correlation to study the spatial- temporal distribution of earthquakes. Parameters based on event location, magnitude and occurrence time are computed for isolated seismicity clusters. Spatial migration behavior is modeled using a weighted-least-squares method. Aftershock-like event clusters do not exhibit significant spatial migration compared with earthquake swarms. Two triggering processes are considered for swarms: slow slip and fluid diffusion, which are distinguished based on a statistical analysis of event migration. The results suggest fluid-induced seismicity is found across southern California, particularly within geothermal areas. In the Salton Sea geothermal field (SSGF), a correlation between seismicity and fluid injection activities is seen. Spatial -temporal variations of earthquake stress drops are investigated in different regions, and a distance- dependence of stress drop from the injection source is found in the SSGF, suggesting the influence of increased pore pressure. Temporal variation of stress drops within mainshock source regions shows that foreshocks and earthquake swarms have lower stress drops than background seismicity and aftershocks. These results, combined with the spatial migration observed for some large foreshock sequences, suggests an aseismic transient process is likely involved in foreshock triggering |
format |
Doctoral or Postdoctoral Thesis |
author |
Chen, Xiaowei |
author_facet |
Chen, Xiaowei |
author_sort |
Chen, Xiaowei |
title |
Aspects of earthquake triggering and seismicity clustering / |
title_short |
Aspects of earthquake triggering and seismicity clustering / |
title_full |
Aspects of earthquake triggering and seismicity clustering / |
title_fullStr |
Aspects of earthquake triggering and seismicity clustering / |
title_full_unstemmed |
Aspects of earthquake triggering and seismicity clustering / |
title_sort |
aspects of earthquake triggering and seismicity clustering / |
publisher |
eScholarship, University of California |
publishDate |
2013 |
url |
http://www.escholarship.org/uc/item/8g78688w http://n2t.net/ark:/20775/bb34826387 |
op_coverage |
1 PDF (1 online resource xviii, 169 pages) |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Antarc* Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctica Southern Ocean |
op_source |
Chen, Xiaowei. (2013). Aspects of earthquake triggering and seismicity clustering /. UC San Diego: Retrieved from: http://www.escholarship.org/uc/item/8g78688w |
op_relation |
http://www.escholarship.org/uc/item/8g78688w qt8g78688w http://n2t.net/ark:/20775/bb34826387 |
op_rights |
public |
_version_ |
1766028968406810624 |