From 2011 to 2013, the CHINArray project led by the Institute of Geophysics, China Earthquake Administration, made the first phase deployment of 350 broadband seismometers at the southeastern margin of the Tibetan plateau. The three‐component records of the CHINArray‐I have been widely used in studying seismic structures beneath the margin under the assumption that the two horizontal components of

With the potential of high temporal and spatial sampling and the capability of utilizing existing fiber‐optic infrastructure, distributed acoustic sensing (DAS) is in the process of revolutionizing geophysical ground‐motion measurements, especially in remote and urban areas, where conventional seismic networks may be difficult to deploy. Yet, for DAS to become an established method, we must ensure

Signal arrival‐time estimation plays a critical role in a variety of downstream seismic analyses, including location estimation and source characterization. Any arrival‐time errors propagate through subsequent data‐processing results. In this article, we detail a general framework for refining estimated seismic signal arrival times along with full estimation of their associated uncertainty. Using the

Networks of autonomous underwater hydrophones (AUHs) are successfully employed for monitoring the low‐level seismicity of mid‐oceanic ridges by detecting hydroacoustic phases known as T waves. For a precise localization of a seismic event from T‐wave arrival times, all AUHs must be synchronized. To this effect, at the beginning of the experiment, all instrument clocks are set to GPS time, which serves

After destructive earthquakes, it is a challenge to estimate magnitude rapidly and accurately for dissemination to emergency responders and the public. Here, we propose criteria to calculate peak ground displacement (PGD) from strong‐motion records, which can be used to calculate unsaturated event magnitude. Using collocated strong‐motion and Global Navigation Satellite Systems observations of five

New seismic stations added to a regional seismic network cannot be used to calculate local magnitude (⁠ML⁠) until a revised regionwide amplitude decay function is developed. Each station must record a minimum number of local and regional earthquakes that meet specific amplitude requirements prior to recalibration of the amplitude decay function. Station component adjustments (⁠dML⁠; Uhrhammer et al

We present a simple and automated approach to estimate primary site‐response resonance, layer thickness, and shear‐wave velocity directly from a dispersion image for a layer over half‐space problem. We demonstrate this for high‐impedance boundary conditions that lie in the upper tens of meters. Our approach eliminates the need for time‐consuming dispersion curve picking and 1D shear‐wave velocity inversion

We investigate seismic site response by inverting seismic ground‐motion spectra for site and source spectral properties, in a region of central Oklahoma, where previous ground‐motion studies have indicated discrepancies between observations and ground‐motion models (GMMs). The inversion is constrained by a source spectral model, which we computed from regional seismic records, using aftershocks as

We address the relation between local amplification and site‐condition indicators derived from in situ geophysical surveys for the estimation of the VS profile, and single‐station recordings processed with horizontal‐to‐vertical spectral ratio technique. Site‐condition indicators, or proxies (e.g., VS30⁠), aim at “summarizing” the description of the local geophysical structure, with a focus on its

The most popular array‐based microtremor survey methods estimate velocity structures from the phase velocities of Rayleigh waves. Using the phase velocity of Love waves improves the resolution of inverted velocity models. In this study, we present a method to estimate the phase velocity of Love waves using rotational array data derived from the horizontal component of microtremors observed using an

In a series of articles, Kawakatsu et al. (2015) and Kawakatsu (2016a,b, 2018) introduced and discussed a new parameter, ηκ⁠, that characterizes the incidence angle dependence (relative to the symmetry axis) of seismic body‐wave velocities in a transverse isotropy (TI) system. During the course of these exercises, several nontrivial consequences of TI were realized and summarized as follows: (1) P‐wave

Explosions are traditionally discriminated from earthquakes, using the relative amplitude of compressional and shear waves at regional and teleseismic distances known as the P/S discriminant. Pyle and Walter (2019) showed this technique to be less robust at shorter distances, in detecting small‐magnitude earthquakes and low‐yield explosions. The disparity is largely due to ground motion from small

The Pacific Earthquake Engineering Research Center Next Generation Attenuation‐West2 database is used to derive a new conditional ground‐motion model (CGMM) and a set of scenario‐based models for estimating cumulative absolute velocity (CAV) for earthquakes in shallow crustal tectonic settings. Random‐effects regressions were performed to develop the conditional model, with random effects across different

Empirical models of geometrical‐, Q‐, t‐star, and kappa‐type attenuation of seismic waves and ground‐motion prediction equations (GMPEs) are viewed as cases of a common empirical standard model describing variation of wave amplitudes with time and frequency. Compared with existing parametric and nonparametric approaches, several new features are included in this model: (1) flexible empirical parameterization

In a companion article, Safarshahi and Morozov (2020) argued that construction of distance‐ and frequency‐dependent models for seismic‐wave amplitudes should include four general elements: (1) a sufficiently detailed (parametric or nonparametric) model of frequency‐independent spreading, capturing all essential features of observations; (2) model parameters with well‐defined and nonoverlapping physical

This article describes a probabilistic site‐response analysis for the city of Oslo, Norway. We first perform a probabilistic seismic hazard analysis (PSHA) for hard rock. Then, we conduct site‐response analyses using Monte Carlo simulations to capture uncertainty in the site profile. We include four base‐case soil profiles to incorporate epistemic uncertainty, and we vary the shear‐wave velocity profile

A comprehensive methodology for the validation of simulated ground motions is presented. The suggested methodology can be geared toward any ground‐motion simulation method and seismic response assessment, in a target engineering application. The methodology is founded on the comparison between conforming groups of ground‐motion waveforms from recordings and simulations and their effect on a representative

We apply three data‐driven selection methods, log‐likelihood (LLH), Euclidean distance‐based ranking (EDR), and deviance information criterion (DIC), to objectively evaluate the predictive capability of 10 ground‐motion models (GMMs) developed from Iranian and worldwide data sets against a new and independent Iranian strong‐motion data set. The data set includes, for example, the 12 November 2017 Mw 7

Predictive models for ground‐motion duration of Mexican subduction interplate and intermediate‐depth intraslab earthquakes are presented. The considered sites are rock sites. For the ground‐motion duration models, the significant durations for ranges between 5%–75%, 5%–95%, and 2.5%–97.5% of Arias intensity are considered for the analyses. The significant duration predictive models are expressed in

This study used earthquake records from China to investigate comprehensively the correlation coefficients between various intensity measures (IMs), including peak ground acceleration, peak ground velocity, spectral acceleration, spectrum intensity, acceleration spectrum intensity, Arias intensity, cumulative absolute velocity, and significant duration. After collection of metadata information, 681

The Dead Sea Transform (DST) dominates the seismicity of Israel and neighboring countries. Whereas the instrumental catalog of Israel (1986–2017) contains mainly M<5 events, the preinstrumental catalog lists 14 M 7 or stronger events on the DST, during the past two millennia. Global Positioning System measurements show that the slip deficit in northern Israel today is equivalent to M>7 earthquake.

Near‐fault fling steps might cause severe damage to near‐fault structures such as bridges or base‐isolated buildings. Therefore, the accurate simulation of ground displacements including fling steps based on fault models is an important issue not only for seismological but also for engineering purposes. The discrete wavenumber (DWN) method (e.g., Bouchon, 2003) has been established as a method to calculate

The selection of ground‐motion prediction equations (GMPEs) to perform seismic hazard assessments is challenging for stable continental regions that lack a sufficient number of recordings. In this study, we implement various ranking methods to test the efficiencies of a wide range of GMPEs against the recordings from three of the largest magnitude inland earthquakes that occurred in the Korean Peninsula

We investigate the dependence of event‐specific ground‐motion residuals in the Ridgecrest region, California. We focus on the impact of using either local (⁠ML⁠) or moment (⁠Mw⁠) magnitude, for describing the source scaling of a regional ground‐motion model. To analyze homogeneous Mw⁠, we compute the source spectra of about 2000 earthquakes in the magnitude range 2.5–7.1, by performing a nonparametric

In this study, we revisit the three largest historical earthquakes in California—the 1857 Fort Tejon, 1872 Owens Valley, and 1906 San Francisco earthquakes—to review their published moment magnitudes, and compare their estimated shaking distributions with predictions using modern ground‐motion models (GMMs) and ground‐motion intensity conversion equations. Currently accepted moment magnitude estimates

This article represents a step toward generalizing and simplifying the procedure for constructing an inversion‐based seismic hazard source model for an interconnected fault system, including the specification of adjustable segmentation constraints. A very simple example is used to maximize understandability and to counter the notion that an inversion approach is only applicable when an abundance of

Did the third Uniform California Earthquake Rupture Forecast (UCERF3) go overboard with multifault ruptures? Schwartz (2018) argues that there are too many long ruptures in the model. Here, I address his concern and show that the UCERF3 rupture‐length distribution matches empirical data. I also present evidence that, if anything, the UCERF3 model could be improved by adding more connectivity to the

The epidemic‐type aftershock sequence model with tapered Gutenberg–Richter (ETAS‐TGR)‐distributed seismic moments is a modification of the classical ETAS‐GR (without tapering) proposed by Kagan in 2002 to account for the finiteness of the deformational energy in the earthquake process. In this article, I analyze the stability of the ETAS‐TGR model by explicitly computing the relative branching ratio

Strong mining‐induced earthquakes are often followed by aftershocks, similar to natural earthquakes. Although the magnitudes of such in‐mine aftershocks are not high, they may pose a threat to mining infrastructure, production, and primarily, people working underground. The existing post‐earthquake mining procedures usually do not consider any aspects of the physics of the mainshock. This work aims

The locations of aftershocks are often observed to be on the same fault plane as the mainshock and used as proxies for its rupture area. Recent developments in earthquake relocation techniques have led to great improvements in the accuracy of earthquake locations, offering an unprecedented opportunity to quantify both the aftershock distribution and the mainshock rupture area. In this study, we design

The 72‐km‐long Teton fault in northwestern Wyoming is an ideal candidate for reconstructing the lateral extent of surface‐rupturing earthquakes and testing models of normal‐fault segmentation. To explore the history of earthquakes on the northern Teton fault, we hand‐excavated two trenches at the Steamboat Mountain site, where the east‐dipping Teton fault has vertically displaced west‐sloping alluvial‐fan

We demonstrate successful crustal imaging via teleseismic P‐wave coda autocorrelation, using data recorded on a 261 station array of vertical‐component high‐frequency geophones in the area of the Bighorn Mountains, Wyoming, U.S.A. We autocorrelate the P‐wave coda of 30 teleseismic events and use phase‐weighted stacking to yield seismic profiles comparable to low‐passed versions of those produced via

Several potentially hazardous northwest‐striking faults in and around the Portland basin, within the fore‐arc of Cascadia, are classified as Quaternary active by the U.S. Geological Survey, but little is known about their Holocene activity. We present new earthquake‐timing constraints on the Gales Creek fault (GCF), a 73 km long, northwest‐trending fault with youthful geomorphic expression located

Holocene crustal faulting in the northern Olympic Peninsula of Washington State manifests in a zone of west‐northwest‐striking crustal faults herein named the North Olympic fault zone, which extends for ∼80 km along strike and includes the Lake Creek–Boundary Creek fault to the east and the Sadie Creek fault and newly discovered scarps to the west. This study focuses on the Sadie Creek fault, which

The Alpine fault is a high slip‐rate plate boundary fault that poses a significant seismic hazard to southern and central New Zealand. To date, the strongest paleoseismic evidence for the onshore southern and central sections indicates that the fault typically ruptures during very large (⁠Mw≥7.7⁠) to great “full‐section” earthquakes. Three paleoseismic trenches excavated at the northeastern end of

The Source Phenomenology Experiment (SPE‐Arizona) included of a series of chemical explosions detonated within a copper mine in Arizona. This study focuses on ground motions from detonations in the copper mine, which are analyzed to assess the uniqueness of the resulting source representation when the source region propagation characteristics have a range of possible models. P‐wave velocities are well

Seismologists distinguish underground nuclear explosions from more commonly occurring earthquakes using moment tensor inversion, high‐frequency P/S amplitude ratios, mb:Ms comparisons, and P‐pP differential travel times. These methods are generally successful for large seismic events (⁠M>3–4⁠) well recorded at regional‐to‐teleseismic distances (⁠>150 km⁠); however, it is unclear whether they can be

The complex postdetonation geologic structures that form after an underground nuclear explosion are hard to constrain because increased heterogeneity around the damage zone affects seismic waves that propagate through the explosion site. Generally, a vertical rubble‐filled structure known as a chimney is formed after an underground nuclear explosion that is composed of debris that falls into the subsurface

The mb : Ms (⁠mb vs. Ms⁠) relationship is an important criterion for screening explosions from earthquakes and has been widely adopted in seismological monitoring by the Comprehensive Nuclear‐Test‐Ban Treaty Organization. In general, the earthquakes have larger Ms than the underground explosions with equivalent mb⁠. However, it has been reported that this recognition criterion failed to identify some

The applicability of the empirical magnitude–yield relations developed for northeast China and Korean Peninsula explosions was investigated for data from northwest China. We collected regional broadband digital seismic data from 13 chemical explosions (CEx) detonated between 6 September and 10 October 2018, on the eastern margin of the Junggar basin, northwest China, five nuclear tests at the Semipalatinsk

In the originally published version of this article, the plots of 5 min Global Navigation Satellite Systems (GNSS) time series shown in Figure 11b were for station CCCC, rather than P595. The corrected Figure 11 showing position time series of P595 is as follows.

BSSA is indebted to the dedicated people who provide peer reviews of submitted papers. Providing a conscientious and timely review is a vital service, both to authors and to readers. The Editorial Board would like to express sincere gratitude to the following people, who completed one or more reviews between November 2019 and October 2020. We apologize for errors or omissions.Brad AagaardRachel AbercrombieNiloufar

Detection and analysis of small magnitude events is valuable for better characterization and understanding of reservoirs in addition to developing strategies for mitigating induced seismicity. Three‐component (3C) receivers, which are now widely used, are commonly deployed in boreholes to provide continuous seismic data amenable to novel and powerful analysis. Using multicomponent continuous records

We present a set of revised ground‐motion models (GMMs) for shallow events at Mt. Etna Volcano. The recent occurrence of damaging events, in particular two of the strongest earthquakes ever instrumentally recorded in the area, has required revising previous GMMs, as these failed to match the observations made for events with local magnitude ML>4.3⁠, above all for sites situated close to the epicenter

The geodynamic features of the north–south seismic zone (NSSZ) and the formation of the Emeishan large igneous province (ELIP) in China remain controversial. In this study, we conducted detailed P‐wave teleseismic tomography studies in the NSSZ and adjacent regions. The results revealed large high‐velocity anomalies beneath the Songpan–Ganzi Block and the South China Block, possibly representing large‐scale

We explore the detectability of M2 tidal tilt in the western part of the United States, using seismic velocity data from 40 stations in the EarthScope Transportable Array (TA) network. We augment these data with data from two additional stations both collocated at the Piñon Flats Observatory (PFO) in southern California (networks TA and Incorporated Research Institutions for Seismology [IRIS] International

The Longmen Shan fault zone (FZ), which consists of the back‐range, the central, and the front‐range faults, acts as the boundary between the Sichuan basin and eastern Tibet. In this study, local and teleseismic waveforms recorded by a 2D small aperture seismic array (176 temporary short‐period seismometers) deployed by China University of Geosciences (Beijing) from 22 October to 20 November 2017 and

Multivariate normality of logarithmic intensity measures (IMs) is conventionally assumed in earthquake engineering applications. This article introduces a vine copula approach as a useful tool for multivariate modeling of IMs. This approach provides a flexible way to decompose a joint distribution into individual marginal distributions and multiple dependences characterized by a cascade of bivariate

Idealization of acceleration response spectra is the basis for construction of target spectra for seismic design and assessment of structures. The adequacy of current methods to reasonably idealize (or smooth) the acceleration spectra of pulse‐like and nonpulse‐like ground motions is examined in this study. The influence of separated pulses on different regions of acceleration response spectrum is

Permanent ground offsets, constituting a prime dataset for constraining final fault‐slip distributions, may not be recovered straightforwardly by double integration of near‐field accelerograms due to tilt and other distorting effects. Clearly, if a way could be found to recover permanent ground offsets from acceleration records, then static datasets would be enlarged, and thus the resolution of fault‐slip

The calculation of earthquake hypocenters requires careful treatment, particularly when prior knowledge of the study area is limited. The prior knowledge, such as wave velocity and data noise, is often assumed to be known in earthquake location algorithms. Such assumptions can greatly simplify the inverse problem but are less general than nonlinear approaches. A nonlinear treatment is of particular

The velocity pulse in near‐fault ground motions has been used as a key characteristic of damaging ground motions. Characterization of the velocity pulse involves three parameters: presence of the pulse, period of the pulse, and amplitude of the pulse. The basic concept behind the velocity pulse is that a large amount of seismic energy is packed into a short time, leading to larger demands on the structure

Earthquake records in the historical literature provide valuable information on the seismic hazard potentials for long recurrence times. The Seoul metropolitan area is the center of the economy and infrastructure in South Korea. Six major earthquakes that occurred around the Seoul metropolitan area during the Joseon dynasty in 1392–1910 are analyzed using a probabilistic joint inversion method based

The steady increase of ground‐motion data not only allows new possibilities but also comes with new challenges in the development of ground‐motion models (GMMs). Data classification techniques (e.g., cluster analysis) do not only produce deterministic classifications but also probabilistic classifications (e.g., probabilities for each datum to belong to a given class or cluster). One challenge is the

Surface ruptures from the 18 April 1906 M∼7.9 San Francisco earthquake were distributed over an ∼35‐meter‐wide zone at San Andreas Lake on the San Francisco Peninsula in California (Schussler, 1906). Since ∼1906⁠, the surface ruptures have been largely covered by water, but with water levels at near‐historic low levels in 2008–2011, we observed that the 1906 surface ruptures were no longer visible

During an earthquake, site effects can play an important role in triggering landslides. To document the seismic response of steep hillslopes, we deployed broadband seismometers across a mountain ridge in Taiwan, in an area with a high earthquake‐induced landslide hazard. The ridge has a simple, representative shape, and landslides have previously occurred there. Our seismometer array has recorded continuously

The main purpose of the site classification or velocity determination at a target site is to obtain or estimate the horizontal site amplification factor (HSAF) at that site during future earthquakes because HSAF would have significant effects on the strong‐motion characteristics. We have been investigating various kinds of methods to delineate the S‐wave velocity structures and the subsequent HSAF

This study examines analog seismograms that were generated when most seismic stations had their own clock for timing, making precise comparison of time between different stations difficult. Availability of accurate relative timing facilitates differential travel‐time analyses, such as seismic tomography and local earthquake relocations, to be performed using data originally recorded on paper or other

The autocorrelation of ambient noise is used to capture reflected waves for crustal and sedimentary structures. We applied autocorrelation to strong‐motion records to capture the reflected waves from sedimentary layers and used them for tuning the S‐wave velocity structure of these layers. Because a sedimentary‐layered structure is complicated and generates many reflected waves, it is important to

We apply a spectral decomposition approach to isolate the source spectra from propagation and site effects and, in turn, to estimate the source parameters of small‐to‐moderate earthquakes that occurred in central Italy. The data set is composed of about 400,000 waveforms relevant to 4111 earthquakes in the moment magnitude range 1.5–6.5, recorded by a high‐density network of stations installed in the