Robust Distributed Earthquake Monitoring with CISN software in Northern California
Abstract
Realtime earthquake monitoring in Northern California passed a milestone this June, when the original joint notification system operated by UC Berkeley's Seismological Laboratory and the USGS in Menlo Park was replaced by the CISN Earthquake Monitoring system. The database plays an integral part in this system, providing coordination for processing and publishing event information, as well as being the repository for event data, instrument metadata and waveforms. Several recent developments to the software system were prerequisites for the transition. (1) Due to the distributed nature of the Northern California network operations at both the BSL and USGS/MP, we enhanced the CISN software to allow distributed continuous waveform processing and the ability to seamlessly merge the processed waveform data from multiple redundant sites into the CISN real-time earthquake processing system. (2) Initially, the CISN code ignored leapseconds, which rendered it incompatible with the Northern California database. In a major CISN-wide effort, all codes were converted to be leapsecond compliant. To maintain compatibility with the Southern California database, one can select whether time output to or received from the database includes leapseconds or not. (3) The project involved revising and improving Caltech's wrapper for the UC Berkeley moment tensor analysis program. This wrapper controls both automatic processing and web review. We developed database tables to receive all supporting information used to calculate the moment tensor, so that any solution can be recalculated, and added many new options to the web interface. By December 2009, the package will use the complete moment tensor program. Since the web interface became available,we have recalculated nearly all the moment tensors for local events in the UC Berkeley moment tensor catalog, so that the mechanisms can be served from the database. (4) With the CISN software transition, Northern California temporarily lost the capability of publishing quicklook earthquake locations, which were available within seconds of the beginning of an earthquake. We have reimplemented this capability in the new software system and are developing the rules necessary to support asynchronously produced hypocenters and magnitudes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFM.S11B1700N
- Keywords:
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- 7200 SEISMOLOGY;
- 7294 SEISMOLOGY / Seismic instruments and networks;
- 7299 SEISMOLOGY / General or miscellaneous