Seismic monitoring is one of the most important approaches for ground-based nuclear explosion monitoring. In order to improve the monitoring capability for low magnitude seismic events, a seismic information system wa...Seismic monitoring is one of the most important approaches for ground-based nuclear explosion monitoring. In order to improve the monitoring capability for low magnitude seismic events, a seismic information system was developed by using the technologies of geographic information system and database. This paper describes the designing and critical technologies of the Seismic Information System in CTBT Verification developed based on ArcGIS and ORACLE platforms. It is a combination of the database storage framework, application programming interface and graphic application software for users to meet their monitoring objectives. Combining the ArcSDE Geodatabase, RDBMS ORACLE and ArcObjects developing technique on COM, not only the multi-sources data has been seamlessly integrated, but also the most functions of ORACLE, for example, consistency, concurrent access, security mechanism, etc, have been reserved. For easy access to the information system we develop two different mechanisms. The first is a menu-driven internal system that is run on NT platforms. The second access mechanism is based on LAN and easily accessible by any web browsers.展开更多
We assess the performance of waveform cross correlation as applied to automatic and interactive processing of the aftershock sequence of the April 11, 2012 Sumatera Ms（IDC） = 8.2 earthquake. The XSEL （cross correla...We assess the performance of waveform cross correlation as applied to automatic and interactive processing of the aftershock sequence of the April 11, 2012 Sumatera Ms（IDC） = 8.2 earthquake. The XSEL （cross correlation standard event list） is compared to the REB （Reviewed Event Bulletin） issued by the IDC （International Data Centre）. The latter includes 1,181 aftershocks between April 11 and May 25. To automatically recover the sequence, sixteen aftershocks were selected from the IDC SEL3 （Standard Event List） available on April 13 and used as master events. Waveform templates from only seven IMS （International Monitoring System） array stations with the largest SNR （signal-to-noise ratio） for the main shock were used to calculate cross correlation coefficients. Approximately 620,000 arrivals were detected and then used to build events according to the IDC definition. After conflict resolution between event hypotheses with similar arrivals found by more than one master, all survived hypotheses populated the XSEL. The total number of distinct hypotheses was 4,924, with 2,763 hypotheses not matched by the REB, i.e. potentially new REB events. To evaluate the quality of the XSEL, we randomly selected a representative portion （-15%） from 2,763 hypotheses and reviewed them interactively according to standard IDC rules and guidelines. There were 119 new REB events built and 145 XSEL hypotheses rejected. Several frequency and probability density distributions have been constructed for all detections, the associated detections, the XSEL detections, the detections in the new REB, and rejected events.展开更多
文摘Seismic monitoring is one of the most important approaches for ground-based nuclear explosion monitoring. In order to improve the monitoring capability for low magnitude seismic events, a seismic information system was developed by using the technologies of geographic information system and database. This paper describes the designing and critical technologies of the Seismic Information System in CTBT Verification developed based on ArcGIS and ORACLE platforms. It is a combination of the database storage framework, application programming interface and graphic application software for users to meet their monitoring objectives. Combining the ArcSDE Geodatabase, RDBMS ORACLE and ArcObjects developing technique on COM, not only the multi-sources data has been seamlessly integrated, but also the most functions of ORACLE, for example, consistency, concurrent access, security mechanism, etc, have been reserved. For easy access to the information system we develop two different mechanisms. The first is a menu-driven internal system that is run on NT platforms. The second access mechanism is based on LAN and easily accessible by any web browsers.
文摘We assess the performance of waveform cross correlation as applied to automatic and interactive processing of the aftershock sequence of the April 11, 2012 Sumatera Ms（IDC） = 8.2 earthquake. The XSEL （cross correlation standard event list） is compared to the REB （Reviewed Event Bulletin） issued by the IDC （International Data Centre）. The latter includes 1,181 aftershocks between April 11 and May 25. To automatically recover the sequence, sixteen aftershocks were selected from the IDC SEL3 （Standard Event List） available on April 13 and used as master events. Waveform templates from only seven IMS （International Monitoring System） array stations with the largest SNR （signal-to-noise ratio） for the main shock were used to calculate cross correlation coefficients. Approximately 620,000 arrivals were detected and then used to build events according to the IDC definition. After conflict resolution between event hypotheses with similar arrivals found by more than one master, all survived hypotheses populated the XSEL. The total number of distinct hypotheses was 4,924, with 2,763 hypotheses not matched by the REB, i.e. potentially new REB events. To evaluate the quality of the XSEL, we randomly selected a representative portion （-15%） from 2,763 hypotheses and reviewed them interactively according to standard IDC rules and guidelines. There were 119 new REB events built and 145 XSEL hypotheses rejected. Several frequency and probability density distributions have been constructed for all detections, the associated detections, the XSEL detections, the detections in the new REB, and rejected events.
