TY - JOUR A1 - Shebalin, Peter A1 - Narteau, Clement A1 - Holschneider, Matthias A1 - Schorlemmer, Danijel T1 - Short-Term earthquake forecasting using early aftershock statistics JF - Bulletin of the Seismological Society of America N2 - We present an alarm-based earthquake forecast model that uses the early aftershock statistics (EAST). This model is based on the hypothesis that the time delay before the onset of the power-law aftershock decay rate decreases as the level of stress and the seismogenic potential increase. Here, we estimate this time delay from < t(g)>, the time constant of the Omori-Utsu law. To isolate space-time regions with a relative high level of stress, the single local variable of our forecast model is the E-a value, the ratio between the long-term and short-term estimations of < t(g)>. When and where the E-a value exceeds a given threshold (i.e., the c value is abnormally small), an alarm is issued, and an earthquake is expected to occur during the next time step. Retrospective tests show that the EAST model has better predictive power than a stationary reference model based on smoothed extrapolation of past seismicity. The official prospective test for California started on 1 July 2009 in the testing center of the Collaboratory for the Study of Earthquake Predictability (CSEP). During the first nine months, 44 M >= 4 earthquakes occurred in the testing area. For this time period, the EAST model has better predictive power than the reference model at a 1% level of significance. Because the EAST model has also a better predictive power than several time-varying clustering models tested in CSEP at a 1% level of significance, we suggest that our successful prospective results are not due only to the space-time clustering of aftershocks. Y1 - 2011 U6 - https://doi.org/10.1785/0120100119 SN - 0037-1106 VL - 101 IS - 1 SP - 297 EP - 312 PB - Seismological Society of America CY - El Cerrito ER - TY - JOUR A1 - Holschneider, Matthias A1 - Narteau, C. A1 - Shebalin, P. A1 - Peng, Z. A1 - Schorlemmer, Danijel T1 - Bayesian analysis of the modified Omori law JF - Journal of geophysical research : Solid earth N2 - In order to examine variations in aftershock decay rate, we propose a Bayesian framework to estimate the {K, c, p}-values of the modified Omori law (MOL), lambda(t) = K(c + t)(-p). The Bayesian setting allows not only to produce a point estimator of these three parameters but also to assess their uncertainties and posterior dependencies with respect to the observed aftershock sequences. Using a new parametrization of the MOL, we identify the trade-off between the c and p-value estimates and discuss its dependence on the number of aftershocks. Then, we analyze the influence of the catalog completeness interval [t(start), t(stop)] on the various estimates. To test this Bayesian approach on natural aftershock sequences, we use two independent and non-overlapping aftershock catalogs of the same earthquakes in Japan. Taking into account the posterior uncertainties, we show that both the handpicked (short times) and the instrumental (long times) catalogs predict the same ranges of parameter values. We therefore conclude that the same MOL may be valid over short and long times. Y1 - 2012 U6 - https://doi.org/10.1029/2011JB009054 SN - 2169-9313 SN - 2169-9356 VL - 117 IS - 6089 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Holschneider, Matthias A1 - Zöller, Gert A1 - Clements, R. A1 - Schorlemmer, Danijel T1 - Can we test for the maximum possible earthquake magnitude? JF - Journal of geophysical research : Solid earth Y1 - 2014 U6 - https://doi.org/10.1002/2013JB010319 SN - 2169-9313 SN - 2169-9356 VL - 119 IS - 3 SP - 2019 EP - 2028 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Strader, Anne A1 - Schneider, Max A1 - Schorlemmer, Danijel T1 - Prospective and retrospective evaluation of five-year earthquake forecast models for California JF - Geophysical journal international KW - Probabilistic forecasting KW - Statistical methods KW - Earthquake interaction KW - fore-casting KW - and prediction KW - Statistical seismology Y1 - 2017 U6 - https://doi.org/10.1093/gji/ggx268 SN - 0956-540X SN - 1365-246X VL - 211 SP - 239 EP - 251 PB - Oxford Univ. Press CY - Oxford ER - TY - GEN A1 - Strader, Anne A1 - Schneider, Max A1 - Schorlemmer, Danijel T1 - Erratum zu: Strader, Anne; Schneider, Max; Schorlemmer, Danijel: Prospective and retrospective evaluation of five-year earthquake forecast models for California (Geophysical Journal International, 211 (2017) 1, S. 239 – 251, https://doi.org/10.1093/gji/ggx268) T2 - Geophysical journal international N2 - S-test results for the USGS and RELM forecasts. The differences between the simulated log-likelihoods and the observed log-likelihood are labelled on the horizontal axes, with scaling adjustments for the 40year.retro experiment. The horizontal lines represent the confidence intervals, within the 0.05 significance level, for each forecast and experiment. If this range contains a log-likelihood difference of zero, the forecasted log-likelihoods are consistent with the observed, and the forecast passes the S-test (denoted by thin lines). If the minimum difference within this range does not contain zero, the forecast fails the S-test for that particular experiment, denoted by thick lines. Colours distinguish between experiments (see Table 2 for explanation of experiment durations). Due to anomalously large likelihood differences, S-test results for Wiemer-Schorlemmer.ALM during the 10year.retro and 40year.retro experiments are not displayed. The range of log-likelihoods for the Holliday-et-al.PI forecast is lower than for the other forecasts due to relatively homogeneous forecasted seismicity rates and use of a small fraction of the RELM testing region. Y1 - 2017 U6 - https://doi.org/10.1093/gji/ggx496 SN - 0956-540X SN - 1365-246X VL - 212 IS - 2 SP - 1314 EP - 1314 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Bayona Viveros, Jose Antonio A1 - von Specht, Sebastian A1 - Strader, Anne A1 - Hainzl, Sebastian A1 - Cotton, Fabrice Pierre A1 - Schorlemmer, Danijel T1 - A Regionalized Seismicity Model for Subduction Zones Based on Geodetic Strain Rates, Geomechanical Parameters, and Earthquake-Catalog Data JF - Bulletin of the Seismological Society of America N2 - The Seismic Hazard Inferred from Tectonics based on the Global Strain Rate Map (SHIFT_GSRM) earthquake forecast was designed to provide high-resolution estimates of global shallow seismicity to be used in seismic hazard assessment. This model combines geodetic strain rates with global earthquake parameters to characterize long-term rates of seismic moment and earthquake activity. Although SHIFT_GSRM properly computes seismicity rates in seismically active continental regions, it underestimates earthquake rates in subduction zones by an average factor of approximately 3. We present a complementary method to SHIFT_GSRM to more accurately forecast earthquake rates in 37 subduction segments, based on the conservation of moment principle and the use of regional interface seismicity parameters, such as subduction dip angles, corner magnitudes, and coupled seismogenic thicknesses. In seven progressive steps, we find that SHIFT_GSRM earthquake-rate underpredictions are mainly due to the utilization of a global probability function of seismic moment release that poorly captures the great variability among subduction megathrust interfaces. Retrospective test results show that the forecast is consistent with the observations during the 1 January 1977 to 31 December 2014 period. Moreover, successful pseudoprospective evaluations for the 1 January 2015 to 31 December 2018 period demonstrate the power of the regionalized earthquake model to properly estimate subduction-zone seismicity. Y1 - 2019 U6 - https://doi.org/10.1785/0120190034 SN - 0037-1106 SN - 1943-3573 VL - 109 IS - 5 SP - 2036 EP - 2049 PB - Seismological Society of America CY - Albany ER - TY - JOUR A1 - Nievas, Cecilia A1 - Pilz, Marco A1 - Prehn, Karsten A1 - Schorlemmer, Danijel A1 - Weatherill, Graeme A1 - Cotton, Fabrice T1 - Calculating earthquake damage building by building BT - the case of the city of Cologne, Germany JF - Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering N2 - The creation of building exposure models for seismic risk assessment is frequently challenging due to the lack of availability of detailed information on building structures. Different strategies have been developed in recent years to overcome this, including the use of census data, remote sensing imagery and volunteered graphic information (VGI). This paper presents the development of a building-by-building exposure model based exclusively on openly available datasets, including both VGI and census statistics, which are defined at different levels of spatial resolution and for different moments in time. The initial model stemming purely from building-level data is enriched with statistics aggregated at the neighbourhood and city level by means of a Monte Carlo simulation that enables the generation of full realisations of damage estimates when using the exposure model in the context of an earthquake scenario calculation. Though applicable to any other region of interest where analogous datasets are available, the workflow and approach followed are explained by focusing on the case of the German city of Cologne, for which a scenario earthquake is defined and the potential damage is calculated. The resulting exposure model and damage estimates are presented, and it is shown that the latter are broadly consistent with damage data from the 1978 Albstadt earthquake, notwithstanding the differences in the scenario. Through this real-world application we demonstrate the potential of VGI and open data to be used for exposure modelling for natural risk assessment, when combined with suitable knowledge on building fragility and accounting for the inherent uncertainties. KW - Building exposure modelling KW - Seismic damage assessment KW - Scenario KW - earthquake KW - Seismic risk KW - Cologne Y1 - 2022 U6 - https://doi.org/10.1007/s10518-021-01303-w SN - 1570-761X SN - 1573-1456 VL - 20 IS - 3 SP - 1519 EP - 1565 PB - Springer CY - Dordrecht ER -