The European Geosciences Union General Assemly 2013 is coming. We have submitted three abstracts and are currently focused on this work. Have no time to do economics/finances. This is one of three abstracts.
Abstract
Abstract
Waveform cross correlation substantially improves detection, phase association, and
event building procedures at the International Data Centre (IDC) of the
Comprehensive Nuclear-Test-Ban Treaty Organization. There were 50% to 100%
events extra to the official Reviewed Event Bulletin (REB) were found in the aftershock sequences
of small, middle size, and very big earthquakes. Several per cent of the events
reported in the REB were not found with cross correlation even when all
aftershocks were used as master events. These REB events are scrutinized in
interactive analysis in order to reveal the reason of the cross correlation
failure. As a corroborative method, we use detailed regional catalogues, which often
include aftershocks with magnitudes between 2.0 and 3.0. Since the resolution
of regional networks is by at least one unit of magnitude higher, the REB
events missed from the relevant regional catalogues are considered as bogus. We
compare events by origin time and location because the regional networks and
the International Monitoring System are based on different sets of seismic
stations and phase comparison is not possible.
Three intracontinental sequences have been studied: after the March 20,
2008 earthquake in China (mb(IDC)=5.4), the May 20, 2012 event in
Italy (mb(IDC)=5.3), and one earthquake (mb(IDC)=5.6) in
Virginia, USA (August 23, 2011).
Overall, most of the events not found by cross correlation are missing
from the relevant regional catalogues. At the same time, these catalogues confirm
most of additional REB events found only by cross correlation. This observation
supports all previous findings of the improved quality of events built by cross
correlation.
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