Presented at the CTBT Science and Technology 2013 Conference, Hofburg, Vienna, June 17-21.
Link to presentation: Dmitry Bobrov, Ivan Kitov, and Mikhail Rozhkov
Abstract
Seismic monitoring of the Comprehensive
Nuclear-Test-Ban Treaty requires a uniform coverage of the earth. The global
use of waveform cross correlation for monitoring purposes is hindered by the
absence of master events outside the zones of seismic activity. To populate the aseismic areas we have
studied two principal approaches. Around
the seismically active areas, we replicate real events best representing
seismicity in a given region and distribute them over a regular grid to
distances ~1000 km. These replicated events are called “grand masters”. For remote aseismic areas, we calculate
synthetic seismograms for a regular grid of master events and a predefined set
of array stations of the International Monitoring System. Both approaches were
tested and showed a resolution similar to the use of real events. Considering
three types of master events, we have created a regular and uniform grid with approximately
100 km spacing between nodes as obtained from the equilibrium distribution of charged
particles over the earth’s surface. We have created three versions of the grid:
v0.1 with only synthetic templates, v0.2
with real masters added where possible, and v0.3 with grand masters added. The
performance of v0.1 has been assessed by full processing of a few data days.
Key words: waveform cross correlation, master events,
seismic monitoring, array seismology, IDC, CTBT
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