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Comprehensive and Topical Evaluations of Earthquake Forecasts in Terms of Number, Time, Space, and Magnitude
Author(s)
Language
English
Obiettivo Specifico
6T. Variazioni delle caratteristiche crostali e precursori
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
3/103(2013)
Pages (printed)
1692–1708
Issued date
June 2013
Alternative Location
Subjects
Abstract
Among scoring methods employed to determine the performance of
probability predictions, the log-likelihood method is the most common and useful.
Although the log-likelihood score evaluates the comprehensive power of forecasts,
we need to further evaluate the topical predictive powers of respective factors of seismicity,
such as total numbers, occurrence times, locations, and magnitudes. For this
purpose, we used the conditional- or marginal-likelihood function based on the observed
events. Such topical scores reveal both strengths and weaknesses of a forecasting
model and suggest the necessary improvements. We applied these scores to the
probability forecasts during the devastating period of March 2011, during which the
Mw 9.0 Off the Pacific Coast of Tohoku-Oki earthquake struck. However, the evaluations
did not suggest that any of the prospective forecast models were consistently
satisfactory. Hence, we undertook two additional types of retrospective forecasting
experiments to investigate the reasons, including the possibility that the seismicity
rate pattern has changed after the M 9 mega-earthquake. In addition, our experiments
revealed a technical difficulty in the one-day forecasting protocol adopted by the
Collaboratory for the Study of Earthquake Predictability (CSEP). Results of further
experiments lead us to recommend specific modifications to the CSEP protocols, leading
to real-time forecasts and their evaluations
probability predictions, the log-likelihood method is the most common and useful.
Although the log-likelihood score evaluates the comprehensive power of forecasts,
we need to further evaluate the topical predictive powers of respective factors of seismicity,
such as total numbers, occurrence times, locations, and magnitudes. For this
purpose, we used the conditional- or marginal-likelihood function based on the observed
events. Such topical scores reveal both strengths and weaknesses of a forecasting
model and suggest the necessary improvements. We applied these scores to the
probability forecasts during the devastating period of March 2011, during which the
Mw 9.0 Off the Pacific Coast of Tohoku-Oki earthquake struck. However, the evaluations
did not suggest that any of the prospective forecast models were consistently
satisfactory. Hence, we undertook two additional types of retrospective forecasting
experiments to investigate the reasons, including the possibility that the seismicity
rate pattern has changed after the M 9 mega-earthquake. In addition, our experiments
revealed a technical difficulty in the one-day forecasting protocol adopted by the
Collaboratory for the Study of Earthquake Predictability (CSEP). Results of further
experiments lead us to recommend specific modifications to the CSEP protocols, leading
to real-time forecasts and their evaluations
Type
article
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