Speaker
Description
Shallow earthquakes with Mw>8-9 usually create extensive aftershock activity with thousands of events with mb>3.5. This is a tremendous challenge for IDC automatic and interactive processing, with the Tohoku-2011 earthquake being a prime example. The SHI IDC processing is fine-tuned to find the smallest events (with fixed human resources), and thousands of similar events within a very short time stresses the system. The waveform cross-correlation (WCC) method - based on the similarity of neighboring seismic sources and using a fixed station set - is an alternative method well suited to the nature of the aftershock sequences, i.e. similar repeating events within a confined area measured by seismic stations of the International Monitoring System. The IDC has been testing the performance of a prototype WCC-based processing pipeline. There is a feature very specific to the IDC: the resulting cross-correlation bulletin (XSEL) contains only the events matching the full set of event definition criteria applied to the Reviewed Event Bulletin. Here we present the testing results as obtained from four different aftershocks sequences. For these sequences we show the effect of varying defining parameters of the prototype WCC pipeline and two sets of master events – the REB and automatic SEL3.
Promotional text
The waveform cross-correlation (WCC) method - based on the similarity of neighboring seismic sources and using a fixed station set - is an alternative method well suited to the nature of the aftershock sequences, i.e. similar repeating events.
