Seismic Hazard Forecasts Research Articles

Forecasting the Long-Term Spatial Distribution of Earthquakes for the 2023 U.S. National Seismic Hazard Model Using Gridded Seismicity

ABSTRACT Probabilistic seismic hazard analyses such as the U.S. National Seismic Hazard Model (NSHM) typically rely on declustering and spatially smoothing an earthquake catalog to estimate a long-term time-independent (background) seismicity rate to forecast future seismicity. In support of the U.S. Geological Survey’s (USGS) 2023 update to the NSHM, we update the methods used to develop this background or gridded seismicity model component of the NSHM. As in 2018, we use a combination of fixed and adaptive kernel Gaussian smoothing. However, we implement two additional declustering methods to account for the fact that declustering is a nonunique process. These new declustering methods result in different forecasts for the locations of future seismicity, as represented by spatial probability density functions that are later combined with a rate model to produce a full gridded earthquake rate forecast. The method updates, particularly in the separation of the spatial and rate models as well as revised regional boundaries, in some places cause substantive changes to the seismic hazard forecast compared to the previous 2018 NSHM. Additional updates to catalog processing and induced seismicity zones also contribute to changes in the gridded seismicity hazard since 2018. However, these changes are well understood and reflect improvements in our modeling of gridded seismicity hazard.

ANALYSIS OF FREQUENCY CONTENT AND STATISTICAL RELATIONSHIP AMONG EARTHQUAKE PARAMETERS OF SEISMIC DATA

The frequency content of the strong-motion seismic data collected from seismic stations by the Bangladesh Meteorological Department (BMD) using GL-S60/120 broadband seismometers of earthquakes in and around Bangladesh is examined. In addition, the statistical relationships among various earthquake parameters, such as the peak ground velocity (PGV), magnitude, epicentral distance, and time of arrival of p-and s-waves of the collected data, are analyzed. Approximate seismic wave velocities are also obtained. The Fourier and wavelet analysis results reveal delicate differences in the frequency content of the p-and s-waves occurring during earthquakes. These results are compared to those generated from the STEAD dataset, which contains seismic waveforms collected in the U.S., France, and Greece regions. Regression analysis on the BMD data derives relationships among the aforementioned parameters. Collected data from some stations show perfect linear relationships among PGV and the travel time of seismic waves with magnitude and epicentral distance, whereas, in other stations, such relationships are not significant. Plausible explanations for these disparities are provided along with similar regression analysis using the STEAD data. The findings are useful for earthquake early-warning systems, geology research, seismic risk zone delineation, and seismic hazard forecasts.

Exploring Australian hazard map exceedance using an Atlas of historical ShakeMaps

This article explores several area-based tests of long-term seismic hazard forecasts for the Australian continent. Using the observed seismicity, ShakeMaps are calculated for earthquakes that are expected to have generated moderate-to-high levels of ground shaking within continental Australia in the past 50 years (January 1972 through December 2021). A “composite ShakeMap” is generated that extracts the maximum peak ground acceleration “observed” in this 50-year period for any site within the continent. The fractional exceedance area of this composite map is compared with four generations of Australian seismic hazard maps for a 10% probability of exceedance in 50 years (~1/500 annual exceedance probability) developed since 1990. In general, all these models appear to forecast higher seismic hazard relative to the ground motions that are estimated to have occurred in the last 50 years, with the most recent hazard model yielding a fractional exceedance area most similar to the target 1/500 annual exceedance probability. The sensitivity of these results to various modeling assumptions was tested by exploring an alternative ground-motion characterization model that forecasts higher overall ground-shaking intensities. The sensitivity of these results is also tested with the interjection of a rare scenario earthquake with an expected regional recurrence of approximately 8700 years. While these area-based analyses do not provide a robust assessment of the performance of the candidate seismic hazard for any specific location given the limited independent data, they do provide—to the first order—a guide to the performance of the respective maps at a continental scale.

Evolution of Short‐Term Seismic Hazard in Alberta, Canada, From Induced and Natural Earthquakes: 2011–2020

AbstractWe generate short‐term seismic hazard maps for the province of Alberta, Canada, from 2011 through 2020. First, we describe the required adaptations to probabilistic seismic hazard analysis to generate short‐term seismic hazard maps, following the Monte Carlo simulation approach. Second, we identify the natural and induced seismic source areas in Alberta and estimate their earthquake recurrence parameters revealing considerable spatio‐temporal variations in the ‐ and ‐values in the different seismic clusters in the province. Areas with the highest short‐term seismic hazard during the last decade in Alberta are related to cases of induced seismicity, including hydraulic fracturing activities in the Duvernay Fm., near Fox Creek, and waste‐water disposal activities near the Musreau Lake. These maps provide a valuable tool to quantify the short‐term evolution in the seismic hazard, which is particularly important considering past and emerging cases of induced seismicity related to the energy sector in Alberta. Furthermore, using parameters from the previous year, we make a seismic hazard forecast for the year 2021. Our analysis provides a baseline of expected short‐term seismic hazard, with inheren uncertainty due to the assumption of unchanged recurrence parameters from the previous year; yet our study reveals pertinent seismicity patterns in line with changing human activities.

Evaluation of Ground-Motion Models for U.S. Geological Survey Seismic Hazard Forecasts: Hawaii Tectonic Earthquakes and Volcanic Eruptions

ABSTRACTThe selection and weighting of ground-motion models (GMMs) introduces a significant source of uncertainty in U.S. Geological Survey (USGS) National Seismic Hazard Modeling Project (NSHMP) forecasts. In this study, we evaluate 18 candidate GMMs using instrumental ground-motion observations of horizontal peak ground acceleration (PGA) and 5%-damped pseudospectral acceleration (0.02–10 s) for tectonic earthquakes and volcanic eruptions, to inform logic-tree weights for the update of the USGS seismic hazard model for Hawaii. GMMs are evaluated using two methods. The first is a total residual visualization approach that compares the probability density function (PDF), mean and standard deviations σ, of the observed and predicted ground motion. The second GMM evaluation method we use is the common total residual probabilistic scoring method (log likelihood [LLH]). The LLH method provides a single score that can be used to weight GMMs in the Hawaii seismic hazard model logic trees. The total residual PDF approach provides additional information by preserving GMM over- and underprediction across a broad spectrum of periods that is not available from a single value LLH score. We apply these GMM evaluation methods to two different data sets: (1) a database of instrumental ground motions from historic earthquakes in Hawaii from 1973 to 2007 (Mw 4–7.3) and (2) available ground motions from recent earthquakes (Mw 4–6.9) associated with 2018 Kilauea eruptions. The 2018 Kilauea sequence contains both volcanic eruptions and tectonic earthquakes allowing for statistically significant GMM comparisons of the two event classes. The Kilauea ground observations provide an independent data set allowing us to evaluate the predictive power of GMMs implemented in the new USGS nshmp-haz software system. We evaluate GMM performance as a function of earthquake depth and we demonstrate that short-period volcanic eruption ground motions are not well predicted by any candidate GMMs. Nine of the initial 18 candidate GMMs fit the observed ground motions and meet established criteria for inclusion in the update of the Hawaii seismic hazard model. A weighted mean of four top performing GMMs in this study (NGAsubslab, NGAsubinter, ASK14, A10) is 50% lower for PGA than for GMMS used in the previous USGS seismic hazard model for Hawaii.

Past meets present to help future seismic hazard forecasts in San Diego

Past meets present to help future seismic hazard forecasts in San Diego

Passive Seismic Tomography as a Tool of Rock Burst Hazard Prognosis in Copper Ore Mine in Poland

In Poland, underground mines of copper ores, which belong to KGHM Polish Copper JSC, have been struggling with seismic dynamic events such as tremors and rock bursts since almost the first years of exploitation i.e. the 70s of the twentieth century. Mining activities infringe the original stress balance and make the rock mass accumulate energy and then release it, which triggers seismic hazard even far away from a tremor epicentre. Therefore, prediction of the position, time and energy of tremors plays a significant role in mining operation especially in work safety. For this purpose, many observation methods including seismology, seismic, geotechnical-geological monitoring, are used; unfortunately, most of them help describe the state of the rock mass after but not prior to the occurrence of the seismic phenomena. Only passive seismic tomography is promising since it can be used to forecast, to some extent, the location of places of seismic energy excessive accumulation. In this method, on the basis of seismic events recorded in a given period, zones of high and low seismic wave velocity are determined (calculated), which in the near future may pose areas of increased seismic activity. The phenomenon of the increase of seismic longitudinal wave velocity with the increase of stress in rocks makes the ground of tomography calculations. The prime purpose of the paper is to assess passive seismic tomography as a means for forecasting and evaluation of seismic and rock burst hazard. To accomplish this, the analysis of seismic activity and archival seismic tomography results (seismic wave velocity zones and seismic anomaly zones) with reference to seismic phenomena, their energy, number and location were carried out. On the basis of obtained the results, the effectiveness of seismic hazard forecast with the use of passive seismic tomography was assessed. The research was carried out for one mining division of the Polkowice-Sieroszowice mine and covered ten years. This division was selected due to its high seismic activity and the permanent use of the passive seismic tomography to assess the seismic risk. Linear correlation and determination coefficients between seismic activity characteristics and seismic anomaly as well as longitudinal wave velocity were calculated. It was found that in the study area the effectiveness of passive seismic tomography in forecasting the seismic hazard is relatively satisfying since about half of the tremors were located within zones of high seismic activity (substantial velocity of P-waves and seismic positive anomalies)..

Machine Learning Methods for Seismic Hazards Forecast

In this paper, we suggest two machine learning methods for seismic hazard forecast. The first method is used for spatial forecasting of maximum possible earthquake magnitudes ( M m a x ), whereas the second is used for spatio-temporal forecasting of strong earthquakes. The first method, the method of approximation of interval expert estimates, is based on a regression approach in which values of M m a x at the points of the training sample are estimated by experts. The method allows one to formalize the knowledge of experts, to find the dependence of M m a x on the properties of the geological environment, and to construct a map of the spatial forecast. The second method, the method of minimum area of alarm, uses retrospective data to identify the alarm area in which the epicenters of strong (target) earthquakes are expected at a certain time interval. This method is the basis of an automatic web-based platform that systematically forecasts target earthquakes. The results of testing the approach to earthquake prediction in the Mediterranean and Californian regions are presented. For the tests, well known parameters of earthquake catalogs were used. The method showed a satisfactory forecast quality.

Tropospheric and Ionospheric Anomalies Induced by Volcanic and Saharan Dust Events as Part of Geosphere Interaction Phenomena

In this work, we assessed the possible relation of ionospheric perturbations observed by Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER), Global Positioning System total electron content (GPS TEC), National Oceanic and Atmospheric Administration (NOAA)-derived outgoing longwave-Earth radiation (OLR), and atmospheric chemical potential (ACP) measurements, with volcanic and Saharan dust events identified by ground and satellite-based medium infrared/thermal infrared (MIR/TIR) observations. The results indicated that the Mt. Etna (Italy) volcanic activity of 2006 was probably responsible for the ionospheric perturbations revealed by DEMETER on 4 November and 6 December and by GPS TEC observations on 4 November and 12 December. This activity also affected the OLR (on 26 October; 6 and 23 November; and 2, 6, and 14 December) and ACP (on 31 October–1 November) analyses. Similarly, two massive Saharan dust episodes, detected by Robust Satellite Techniques (RST) using Spinning Enhanced Visible and Infrared Imager (SEVIRI) optical data, probably caused the ionospheric anomalies recorded, based on DEMETER and GPS TEC observations, over the Mediterranean basin in May 2008. The study confirmed the perturbing effects of volcanic and dust events on tropospheric and ionospheric parameters. Further, it demonstrated the advantages of using independent satellite observations to investigate atmospheric phenomena, which may not always be well documented. The impact of this increased detection capacity in reducing false positives, in the framework of a short-term seismic hazard forecast based on the study of ionospheric and tropospheric anomalies, is also addressed.

Characteristic Earthquake Magnitude Frequency Distributions on Faults Calculated From Consensus Data in California

AbstractAn estimate of the expected earthquake rate at all possible magnitudes is needed for seismic hazard forecasts. Regional earthquake magnitude frequency distributions obey a negative exponential law (Gutenberg‐Richter), but it is unclear if individual faults do. We add three new methods to calculate long‐term California earthquake rupture rates to the existing Uniform California Earthquake Rupture Forecast version 3 efforts to assess method and parameter dependence on magnitude frequency results for individual faults. All solutions show strongly characteristic magnitude‐frequency distributions on the San Andreas and other faults, with higher rates of large earthquakes than would be expected from a Gutenberg‐Richter distribution. This is a necessary outcome that results from fitting high fault slip rates under the overall statewide earthquake rate budget. We find that input data choices can affect the nucleation magnitude‐frequency distribution shape for the San Andreas Fault; solutions are closer to a Gutenberg‐Richter distribution if the maximum magnitude allowed for earthquakes that occur away from mapped faults (background events) is raised above the consensus threshold ofM = 7.6, if the moment rate for background events is reduced, or if the overall maximum magnitude is reduced fromM = 8.5. We also find that participation magnitude‐frequency distribution shapes can be strongly affected by slip rate discontinuities along faults that may be artifacts related to segment boundaries.

Evaluation of Ground‐Motion Models for USGS Seismic Hazard Forecasts: Induced and Tectonic Earthquakes in the Central and Eastern United States

Evaluation of Ground‐Motion Models for USGS Seismic Hazard Forecasts: Induced and Tectonic Earthquakes in the Central and Eastern United States

2018 One‐Year Seismic Hazard Forecast for the Central and Eastern United States from Induced and Natural Earthquakes

2018 One‐Year Seismic Hazard Forecast for the Central and Eastern United States from Induced and Natural Earthquakes

Aftershock Decay Rates in the Iranian Plateau

Motivated by the desire to have more information following the occurrence of damaging events, the main purpose of this article is to study aftershock sequence parameters in the Iranian plateau. To this end, the catalogue of the Iranian earthquakes between 2002 to the end of 2013 has been collected and homogenized among which 15 earthquakes have been selected to study their aftershock decay rates. For different tectonic provinces, the completeness magnitudes (Mc) of the earthquake catalogue have been calculated in different time intervals. Also, the Mc variability in spatial and temporal windows has been determined for each selected event. For major Iranian earthquakes, catalogue of aftershocks has been collected thanks to three declustering methods: first, the classical windowing method of Gardner and Knopoff (Bull Seismol Soc Am 64:1363–1367, 1974); second, a modified version of this using spatial windowing based on the Wells and Coppersmith (Bull Seismol Soc Am 84:974–1002, 1994) relations; and third, the Burkhard and Grunthal (Swiss J Geosci 102:149–188, 2009) scheme. Effects of the temporal windows also have been investigated using the time periods of 1 month, 100 days, and 1 year in the declustering method of Gardner and Knopoff (Bull Seismol Soc Am 64:1363–1367, 1974). In the next step, the modified Omori law coefficients have been calculated for the 15 selected earthquakes. The calibrated regional generic model describing the temporal and magnitude distribution of aftershocks is of interest for time-dependent seismic hazard forecasts. The regional characteristics of the aftershock decay rates have been studied for the selected Iranian earthquakes in the Alborz, Zagros and Central Iran regions considering their different seismotectonics regimes. However, due to the lack of sufficient data, no results have been reported for the Kopeh-Dagh and Makran seismotectonic regions.

An Approach to the short- and long-term forecasting of strong earthquakes: A case study of the M w = 9.0 Tohoku earthquake, Japan, March 11, 2011

Seismic hazard forecasts submitted in real-time mode to the Kamchatkan Branch of the Russian Expert Council (KB REC) on Earthquake Prediction, Seismic Hazard, and Risk Assessment are described. In the first long-term forecasts (September 7 and November 9, 2009), based on the GLOBAS_place technique (GLOBal Activation of Seismicity), we forecasted the occurrence of earthquakes with M ≥ 6.6 in the region of 35° N–40° N (Japan) and in three other regions of the world. In the forecasts submitted on February 25, and March 2 and 3, 2011, we indicated the possibility of more than one earthquake with Mw ≥ 8 occurring starting from noon, March 3. Forecasts were based on the GLOBAS techniques and recording of remote precursors using instrumental methods. Precursors were recorded before the Tohoku earthquake with a preceding time of up to 28 days based on the dynamics of molecular hydrogen (Kamchatka) and less than 8 days based on the bulk deformations in the area of town of Aleksandrov (Moscow Syneclise, East European Craton). A complex analysis of the data, performed within the framework of the techniques used, confirms the possibility of forecasting the time of occurrence, magnitude, and place of strong earthquakes with M ≥ 8.

Hillslopes Record the Growth and Decay of Landscapes

Earth's surface archives the combined history of tectonics and erosion, which tend to roughen landscapes, and sediment transport and deposition, which smooth them. We analyzed hillslope morphology in the tectonically active Dragon's Back Pressure Ridge in California, United States, to assess whether tectonic uplift history can be reconstructed using measurable attributes of hillslope features within landscapes. Hilltop curvature and hillslope relief mirror measured rates of vertical displacement caused by tectonic forcing, and their relationships are consistent with those expected when idealizing hillslope transport as a nonlinear diffusion process. Hilltop curvature lags behind relief in its response to changing erosion rates, allowing growing landscapes to be distinguished from decaying landscapes. Numerical modeling demonstrates that hillslope morphology may be used to infer changes in tectonic rates.

Update of normative seismic zoning in the framework of the integrated information system for the seismic safety of Russia

The article deals with updating databases and the general seismic zoning maps of the Russian territory (GSZ-97). Development of new maps (GSZ-2012) is considered. Recommendations on updating the building codes are made. The article reports on the development of the Integrated Information System “Seismic Safety of Russia” that involves operation of the specialized interactive maps of seismic hazard forecast.

Time-, Distance-, and Magnitude-Dependent Foreshock Probability Model for New Zealand

The possibility that a moderate earthquake may be followed by an equal or larger one (foreshock probability) increases the hazard in its immediate vicinity for a short time by an order of magnitude or more. Thus, foreshock probabilities are of interest for time-dependent seismic hazard forecasts. We calculate the probability of an initial earthquake (a foreshock) being followed by a mainshock in New Zealand, considering the parameters of elapsed time and distance and magnitude differences between foreshock and mainshock. We use nonaftershock events between 1964 and 2007, with magnitude ≥4.0 and shallower than 40 km, separating the catalog into events within and outside the Taupo volcanic zone (TVZ). We provide a model for the probability P ( t , r , δM ) that at time t after a potential foreshock (FS) of magnitude M FS and at distance r , a mainshock with magnitude M FS+ δM will occur: P ( t , r , δM )= P ×10(- BδM )( t + c t )- p t ( r + c r )- p r , where P , B , p t , c t , p r , and c r are constants to be determined. We find that (1) binning data using fixed intervals of time or space before fitting the parameters returns different values than a more robust approach of fitting directly the entire range, (2) foreshock probabilities decrease with increasing interevent time as described by a modified Omori law with an exponent p t close to 1 (0.9±0.2 [TVZ] and 0.8±0.1 elsewhere—uncertainty estimates are 95% confidence intervals throughout this study), (3) foreshock probabilities decrease with increasing epicentral distance also following a modified Omori type decay with exponent p r of 0.9±0.2 (non-TVZ) and 1.7±0.6 (TVZ), and (4) the mainshock magnitude distribution follows the Gutenberg–Richter relationship ( B =1.0±0.17 [non-TVZ] and 1.5±0.5 [TVZ]). The differences between the TVZ and the rest of New Zealand are consistent with higher attenuation in the region, deduced from previous studies.

Seismic Hazard Inferred from Tectonics: California

Research Article| January 01, 2007 Seismic Hazard Inferred from Tectonics: California Peter Bird; Peter Bird Search for other works by this author on: GSW Google Scholar Zhen Liu Zhen Liu 1Now at: Jet Propulsion Laboratory. Search for other works by this author on: GSW Google Scholar Seismological Research Letters (2007) 78 (1): 37–48. https://doi.org/10.1785/gssrl.78.1.37 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Peter Bird, Zhen Liu; Seismic Hazard Inferred from Tectonics: California. Seismological Research Letters 2007;; 78 (1): 37–48. doi: https://doi.org/10.1785/gssrl.78.1.37 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search In this paper we propose simple methods for estimating long-term average seismicity of any region, based on a local kinematic model of surface velocities and an existing global calibration of plate-boundary seismicity. We apply the method to California and obtain a long-term forecast of seismicity that exceeds the levels seen in several 20th-century catalogs. This contribution is the third in a series describing a project informally known as Seismic Hazard Inferred from Tectonics (SHIFT). Its goal is to realize the promise of plate tectonic theory to provide long-term seismicity forecasts (and, eventually, seismic hazard forecasts) more reliable than those based... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Kaliningrad earthquake of September 21, 2004 and seismic hazard forecast in the Belarusian-Baltic region

The paper deals with the earthquakes that took place in the Kaliningrad region (Russia) on 21 September 2004 and were felt in the territories of Poland, Lithuania, Latvia, Estonia, Belarus and Finland. Data on space and time co-ordinates and dynamic parameters of these earthquake foci available from international centers and various seismological groups are analyzed. A degree of reliability of the results obtained is discussed.