Journal
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
Volume 122, Issue 10, Pages 7966-7986Publisher
AMER GEOPHYSICAL UNION
DOI: 10.1002/2017JB014495
Keywords
backprojection; earthquake source imaging; uncertainty analysis; Japan subduction zone
Categories
Funding
- Seismological Facilities for the Advancement of Geoscience and EarthScope (SAGE) Proposal of the National Science Foundation [EAR-1261681]
- National Science Foundation (NSF) at Scripps Institution of Oceanography, UC San Diego [EAR-1620251]
- Division Of Earth Sciences
- Directorate For Geosciences [1620251] Funding Source: National Science Foundation
Ask authors/readers for more resources
We investigate possible biasing effects of inaccurate timing corrections on teleseismic P wave backprojection imaging of large earthquake ruptures. These errors occur because empirically estimated time shifts based on aligning P wave first arrivals are exact only at the hypocenter and provide approximate corrections for other parts of the rupture. Using the Japan subduction zone as a test region, we analyze 46 M6-M7 earthquakes over a 10year period, including many aftershocks of the 2011 M9 Tohoku earthquake, performing waveform cross correlation of their initial P wave arrivals to obtain hypocenter timing corrections to global seismic stations. We then compare backprojection images for each earthquake using its own timing corrections with those obtained using the time corrections from other earthquakes. This provides a measure of how well subevents can be resolved with backprojection of a large rupture as a function of distance from the hypocenter. Our results show that backprojection is generally very robust and that the median subevent location error is about 25km across the entire study region (approximate to 700km). The backprojection coherence loss and location errors do not noticeably converge to zero even when the event pairs are very close (<20km). This indicates that most of the timing differences are due to 3-D structure close to each of the hypocenter regions, which limits the effectiveness of attempts to refine backprojection images using aftershock calibration, at least in this region.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available