2004 Fiscal Year Final Research Report Summary
Comprehensive study for statistical prediction of seismic activity
| Project/Area Number |
14380128
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Statistical science
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| Research Institution | The Institute of Statistical Mathematics |
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Principal Investigator |
OGATA Yosihiko The Institute of Statistical Mathematics, Department of Statistical Methodology, Professor, 調査実験解析研究系, 教授 (70000213)
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| Co-Investigator(Kenkyū-buntansha) |
TANEMURA Masaharu The Institute of Statistical Mathematics, Department of Statistical Methodology, Professor, 調査実験解析研究系, 教授 (80000214)
HIGUCHI Tomoyuki The Institute of Statistical Mathematics, Department of Prediction and Control, Professor, 予測制御研究系, 教授 (70202273)
SATO Seisho The Institute of Statistical Mathematics, Department of Prediction and Control, Assistant Professor, 予測制御研究系, 助教授 (60280525)
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| Project Period (FY) |
2002 – 2004
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| Keywords | ETAS model / change-point problem / relative quiescence and activation / Coulomb stress-changes / precursory aseismic slip / detection rate of earthquake / probability forecast of aftershocks |
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| Research Abstract |
One important outcome emerging from this study is the use of statistical models as diagnostic tools to identify anomalous trends and other features of the seismicity pattern. The ETAS model itself is an extremely useful tool in detecting anomalous features in seismic activity, including aftershock activity, and in identifying and defining seismic quiescence. The results of comparing the actual seismicity rates with the rates predicted by the ETAS model have very interesting implications for the physical interpretation of the processes controlling the evolution of seismicity. The connections between seismicity rate changes and coseismic stress changes have been emphasized and discussed in several important recent publications. In particular, it is worth noting that the relative quiescence defined in relation to the ETAS model represents the best currently available definition and physical interpretation of the "stress shadow". In other words, this represents the most robust definition t
… More
he stress shadow and the proposed numerical approach is the best solution to identify seismicity rate reductions. This has been recognized by the scientific community.
We have proposed the Hierarchical Space-Time ETAS model that is extended for applying space-time coordinates of earthquake catalogs. Regional earthquake occurrence rate is modeled as a function of previous activity whose specific form is based on empirical laws such as the modified Omori formula and the Utsu-Seki scaling law of aftershock area against magnitude. Its parameters, including the p-value of the aftershock decay rate, can vary from place to place. This model is used to visualize features of the regional seismic activities in and around Japan. Among the five parameters of the model, the spatial variation of the K-parameter (the productivity of aftershocks) can be well correlated with asperity locations. Furthermore, the model enables us to enhance the regions where the actual occurrence rates deviate systematically from the modeled one. In particular, the relative quiescence or the seismic gap of the second type is of great concern. Also, the incidental outcomes of our research include the stochastc clustering / declustering procedure by the space-time ETAS model, which enables another diagnostic tool to examine the adequacy of a space-time model when we are given a dataset. Less
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Research Products
(45 results)
