Short- and Long-Term Earthquake Forecasts for California and Nevada

Kagan, Yan Y.; Jackson, David D.

doi:10.1007/s00024-010-0073-5

Cited by 9 publications

(2 citation statements)

References 18 publications

(26 reference statements)

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“…Within both the M ≥ 2 and the M ≥ 3 forecast group, K 3 achieved the highest gain, followed by the ensemble model and ETAS. According to the T-and W-tests, all three models currently achieve significantly larger gains than any other model, including the STEP model by Gerstenberger et al (2005) and the critical-branching model by Kagan and Jackson (2010). Accumulating target earthquakes will enable more meaningful distinctions between the information content of the forecasts.…”

Section: Discussionmentioning

confidence: 99%

Adaptive Smoothing of Seismicity in Time, Space, and Magnitude for Time-Dependent Earthquake Forecasts for California

Helmstetter

Werner

2014

Bulletin of the Seismological Society of America

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We present new methods for short-term earthquake forecasting that employ space, time, and magnitude kernels to smooth seismicity. These methods are purely statistical and rely on very few assumptions about seismicity. In particular, we do not use Omori-Utsu law, and only one of our two new models assumes a Gutenberg-Richter law to model the magnitude distribution; the second model estimates the magnitude distribution nonparametrically with kernels. We employ adaptive kernels of variable bandwidths to estimate seismicity in space, time, and magnitude bins. To project rates over short time scales into the future, we simply assume persistence, that is, a constant rate over short time windows. The resulting forecasts from the two new kernel models are compared with those of the epidemic-type aftershock sequence (ETAS) model generated by . Although our new methods are simpler and require fewer parameters than ETAS, the obtained probability gains are surprisingly close. Nonetheless, ETAS performs significantly better in most comparisons, and the kernel model with a Gutenberg-Richter law attains larger gains than the kernel model that nonparametrically estimates the magnitude distribution. Finally, we show that combining ETAS and kernel model forecasts, by simply averaging the expected rate in each bin, can provide greater predictive skill than ETAS or the kernel models can achieve individually.

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Section: Discussionmentioning

confidence: 99%

Adaptive Smoothing of Seismicity in Time, Space, and Magnitude for Time-Dependent Earthquake Forecasts for California

Helmstetter

Werner

2014

Bulletin of the Seismological Society of America

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“…The body wave magnitude ( m b ) and surface wave magnitudes ( M s ) can be analytically converted to M w . However, Kagan [] found inconclusive results, and Kagan and Jackson [] used maximum magnitude for long and short term earthquake forecast in California and Nevada. We also use maximum magnitude without converting m b / M s to M w for this study.…”

Section: Data: Catalog Homogeneity and Completenessmentioning

confidence: 99%

A non‐stationary epidemic type aftershock sequence model for seismicity prior to the December 26, 2004 M 9.1 Sumatra‐Andaman Islands mega‐earthquake

Bansal

Ogata

2013

JGR Solid Earth

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.[1] We study temporal changes in seismicity in Sumatra-Andaman Islands region before the M 9.1 earthquake of December 26, 2004. We applied the epidemic type aftershock sequence (ETAS) models to the seismicity. The two-stage non-stationary ETAS model with a single change-point provides a better statistical fit to the seismicity data than the stationary ETAS model throughout the whole period. We made further change-point analysis of data sets by dividing into two sub-regions. The best fitted models suggest that the seismic activation relative to the ETAS rates started in the middle of July 2000 (about 4.5 years before the M 9.1 earthquake). This includes an increase in the background seismicity rates, particularly in the southern part of the seismogenic zone near the epicenter. A space-time ETAS model also suggests that the background seismicity throughout the entire Sumatra-Andaman Islands area had increased after the change-point time.Citation: Bansal, A. R., and Y. Ogata (2013), A non-stationary epidemic type aftershock sequence model for seismicity prior to the

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Earthquake Forecasting in Diverse Tectonic Zones of the Globe

Kagan

Jackson

2010

Pure Appl. Geophys.

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We present a simple method for long-and shortterm earthquake forecasting (estimating earthquake rate per unit area, time, and magnitude). For illustration we apply the method to the Pacific plate boundary region and the Mediterranean area surrounding Italy and Greece. Our ultimate goal is to develop forecasting and testing methods to validate or falsify common assumptions regarding earthquake potential. Our immediate purpose is to extend the forecasts we made starting in 1999 for the northwest and southwest Pacific to include somewhat smaller earthquakes and then adapt the methods to apply in other areas. The previous forecasts used the CMT earthquake catalog to forecast magnitude 5.8 and larger earthquakes. Like our previous forecasts, the new ones here are based on smoothed maps of past seismicity and assume spatial clustering. Our short-term forecasts also assume temporal clustering. An important adaptation in the new forecasts is to abandon the use of tensor focal mechanisms. This permits use of earthquake catalogs that reliably report many smaller quakes with no such mechanism estimates. The result is that we can forecast earthquakes at higher spatial resolution and down to a magnitude threshold of 4.7. The new forecasts can be tested far more quickly because smaller events are considerably more frequent. Also, our previous method used the focal mechanisms of past earthquakes to estimate the preferred directions of earthquake clustering, however the method made assumptions that generally hold in subduction zones only. The new approach escapes those assumptions. In the northwest Pacific the new method gives estimated earthquake rate density very similar to that of the previous forecast.

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Short- and Long-Term Earthquake Forecasts for California and Nevada

Cited by 9 publications

References 18 publications

Adaptive Smoothing of Seismicity in Time, Space, and Magnitude for Time-Dependent Earthquake Forecasts for California

Adaptive Smoothing of Seismicity in Time, Space, and Magnitude for Time-Dependent Earthquake Forecasts for California

A non‐stationary epidemic type aftershock sequence model for seismicity prior to the December 26, 2004 M 9.1 Sumatra‐Andaman Islands mega‐earthquake

Earthquake Forecasting in Diverse Tectonic Zones of the Globe

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