Comparing the Performance of Japan’s Earthquake Hazard Maps to Uniform and Randomized Maps

Brooks, Edward Μ.; Stein, Seth; Spencer, Bruce D.

doi:10.1785/0220150100

Cited by 17 publications

(11 citation statements)

References 29 publications

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“…For the region where the 2011 event happened the recent Japanese hazard maps had estimated a lower probability of 0.1% (almost at the background level as elsewhere along the coast of Japan) compared to the Nanka-to-Tokai area where estimates reached close to 100% [115], and similar discrepancies have been observed elsewhere in the world, notably Haiti, China, Algeria and Italy [114,116]. Brooks et al [117] show that uniform or randomized maps perform better than the Japanese National Hazard Maps, at least using the metric inherent in these maps.…”

Section: Paradigm Changes Since 2011 In Japan and Elsewherementioning

confidence: 76%

Tsunamis: bridging science, engineering and society

Kânoğlu

Titov

Bernard

et al. 2015

Phil. Trans. R. Soc. A.

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Tsunamis are high-impact, long-duration disasters that in most cases allow for only minutes of warning before impact. Since the 2004 Boxing Day tsunami, there have been significant advancements in warning methodology, pre-disaster preparedness and basic understanding of related phenomena. Yet, the trail of destruction of the 2011 Japan tsunami, broadcast live to a stunned world audience, underscored the difficulties of implementing advances in applied hazard mitigation. We describe state of the art methodologies, standards for warnings and summarize recent advances in basic understanding, and identify cross-disciplinary challenges. The stage is set to bridge science, engineering and society to help build up coastal resilience and reduce losses.

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Section: Paradigm Changes Since 2011 In Japan and Elsewherementioning

confidence: 76%

Tsunamis: bridging science, engineering and society

Kânoğlu

Titov

Bernard

et al. 2015

Phil. Trans. R. Soc. A.

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“…We have previously found (Brooks et al, 2016) that some hazard maps behave quite differently from the ideal. Figure 1(b) compares the largest known shaking at points within Japan in 510 years to that predicted by the Japanese National Hazard (JNH) map with a 475-year return period.…”

Section: Prior Resultsmentioning

confidence: 99%

“…Our earlier paper (Brooks et al, 2016) considered Geller's (2011) proposal that "all of Japan is at risk from earthquakes, and the present state of seismological science does not allow us to reliably differentiate the risk level in particular geographic areas", in which case maps less detailed than present ones would be preferable. We examined how well a 510-year-long record of earthquake shaking in Japan is described by the current JNH maps compared to uniform and randomised versions of these maps.…”

Section: Prior Resultsmentioning

confidence: 99%

“…We repeated these comparisons for an updated map that incorporated shaking from the 2011 Tohoku event. Brooks et al (2016) noted that adding these high shaking values improved the JNH maps' performance as measured by both metrics, but their performance relative to uniform and randomised maps remained the same. Similarly, we found that the effects of smoothing on performance remained essentially the same.…”

Section: Smoothed Map Performancementioning

confidence: 95%

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Investigating the effects of smoothing on the performance of earthquake hazard maps

Brooks

Stein

Spencer

2017

IJEIE

Self Cite

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We explore whether less detailed probabilistic hazard maps might perform better by assessing how smoothing Japan's national earthquake hazard maps affects their fit to a 510-year record of shaking. As measured by the fractional exceedance metric implicit in such probabilistic hazard maps, simple smoothing over progressively larger areas improves the maps' performance such that in the limit a uniform map performs best. However, using the squared misfit between maximum observed shaking and that predicted as a metric, map performance improves up to a ~75-150 km smoothing window, and then decreases with further smoothing. This result suggests that the probabilistic hazard models and the resulting maps may be over-parameterized, in that including too high a level of detail to describe past and future earthquakes may lower the maps' ability to predict future shaking.

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“…This validation exercise (validation, verification, and testing are used in this article as synonyms, although workers in different fields may assign different meanings to these terms) has been receiving increasing attention in recent years (Ordaz and Reyes, 1999;Stirling and Petersen, 2006;Albarello and D'Amico, 2008;Fujiwara et al, 2009;Miyazawa and Mori, 2009;Stirling and Gerstenberger, 2010;Mezcua et al, 2013;Tasan et al, 2014;Brooks et al, 2016), although it has not yet been a routine and standard process such as how meteorologists treat the weather forecast (e.g., the quality of weather forecasts is regularly published by the European Centre for Medium-Range Weather Forecasts [ECMWF], see Data and Resources). The lack of a standard validation may have induced arguments over whether a PSHA model is serving its purpose, especially after a significant earthquake occurs not in the most expected place and/or is not of the most expected size (Stein et al, 2011(Stein et al, , 2012Hanks et al, 2012;Stirling, 2012;Frankel, 2013a,b).…”

Section: Introductionmentioning

confidence: 99%

A Comparison between the Forecast by the United States National Seismic Hazard Maps with Recent Ground‐Motion Records

Mak

Schorlemmer

2016

Bulletin of the Seismological Society of America

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Confidence in scientific models accumulates by continuously validating the model's predictions by observations. We compared the seismic-hazard forecasts of the four published versions of the U.S. Geological Survey National Seismic Hazard Maps with observed ground motions. A large dataset is necessary for a statistically meaningful comparison, and so our comparison was based on an aggregated approach such that the observations and the forecast in a region (California, and the central and eastern United States [CEUS]) were combined and compared as a whole. We used instrumental records in California and macroseismic intensity in the CEUS since 2000 as the observation, which was largely prospective to the hazard maps. We verified that the observed seismic hazard based on macroseismic intensity was consistent with that based on instrumental records, making model evaluation in the CEUS, for which instrumental records were almost nonexistent, viable. The observed hazard was found to be generally consistent with the forecasted one for peak ground acceleration (PGA) in California and for both PGA and spectral acceleration at 1 s (SA1) in the CEUS. Forecasted hazard for SA1 for California appeared to be conservative. Recent versions of the hazard map were in better agreement with observations in California. Small earthquakes, as expected, were found to have insignificant impact on SA1. Induced earthquakes in the CEUS have increased the observed seismic hazard but did not invalidate the hazard model as a whole. We examined the resolving power of the test by computing its statistical power.

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Comparing the Performance of Japan’s Earthquake Hazard Maps to Uniform and Randomized Maps

Cited by 17 publications

References 29 publications

Tsunamis: bridging science, engineering and society

Tsunamis: bridging science, engineering and society

Investigating the effects of smoothing on the performance of earthquake hazard maps

A Comparison between the Forecast by the United States National Seismic Hazard Maps with Recent Ground‐Motion Records

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