We study the rupture process of the 1992 Landers earthquake. To limit the tradeoff between slip amplitude and rupture time that affects solutions using only seismological data, we adopt a two-step approach. We first constrain the slip distribution and its uncertainty by independent geodetic data to recover in the second step the temporal details of the rupture propagation. The first step consists of an inversion of interferometric data and Global Positioning System measurements, both independently and together, to constrain slip distribution on a three-segment fault model along both strike and dip direction. We use a genetic algorithm to test the uniqueness of the solution and a least squares formulation to find the model which best fits the data. We conclude from the results of these geodetic inversions that interferometric data are rich enough to access the slip distribution in the case of the Landers earthquake. Since the surface deformations are more sensitive to shallow slip in our configuration, the slip amplitude is better resolved near the surface than at depth. The resulting slip distribution is in agreement with geological observations at the surface and confirms the heterogeneous nature of the Landers earthquake. Most of the slip occurs at shallow depths, on the Homestead Valley fault (second segment), with a maximum value of around 7 m. Another high slip zone is observed on the Johnson Valley fault (first segment) at 8 km depth. In the second step, we invert strong motion data with the a priori final slip amplitude and its uncertainty deduced from geodetic data to constrain the time history of the rupture process. This second step emphasizes a strong variation of the temporal development of the earthquake. Fast rupture front velocities appear within high slip zones, and the rupture slows when it encounters a resistance along the fault. On average, the rupture front propagates with velocities close to the S wave velocity and terminates about 20 s after initiation. The large variations in both slip amplitude and rupture velocity suggest that the rupture process is better described by successively breaking asperities than by a pulse propagating with constant velocity. 1. Introduction In seismology, basic problems of initiation, propagation, and healing of the rupture process are still not well understood. Since the near-field strong ground motion records of the Imperial Valley earthquake [Olson and Apsel, 1982; Hartzell and Heaton, 1983; Archuleta, 1984], rupture heterogeneity became evident. This heterogeneity is probably generated by a combination of the static prestress field due to tectonic forces, past seismicity [Kanamori and Stewart, 1978], fault geometry [Scholz, 1989; Cotton and Campillo, 1995], and the effect of the dynamic process governed by Paper number 1999JB900078. 0148-0227/99/1999JB 900078509.00 friction [Carlson and Langer, 1989; Cochard and Madariaga, 1994]. In order to understand the main origin of the rupture complexity, seismologists adopt two approaches. On the one hand, forward dy...

This paper presents the overall procedure followed in order to assemble the most recent pan-European strong-motion databank: Reference Database for Seismic Ground-Motion in Europe (RESORCE). RESORCE is one of the products of the SeIsmic Ground Motion Assessment (SIGMA; projet-sigma.com) project. RESORCE is intended to be a single integrated accelerometric databank for Europe and surrounding areas for use in the development and testing of ground-motion models and for other engineering seismology and earthquake engineering applications. RESORCE aims to contribute to the improvement of earthquake risk studies in Europe and surrounding areas. RESORCE principally updates and extends the previous pan-European strong-motion databank (Ambraseys et al. in Bollettino di Geofisica Teorica ed Applicata 45:113-129, 2004a) with recently compiled Greek, Italian, Swiss and Turkish accelerometric archives. The updates also include earthquake-specific studies published in recent years. The current content of RESORCE includes 5,882 multi-component and uniformly processed accelerograms from 1,814 events and 1,540 strong-motion stations. The moment magnitude range covered by RESORCE is {Mathematical expression}. The source-to-site distance interval extends to 587 km and distance information is given by the common point- and extended-source distance measures. The paper presents the current features of RESORCE through simple statistics that also quantify the differences in metadata and strong-motion processing with respect to the previous version of the pan-European strong-motion databank

Abstract-On September 15th, 2007, around 11:45 local time in Peru, near the Bolivian border, the atmospheric entry of a meteoroid produced bright lights in the sky and intense detonations. Soon after, a crater was discovered south of Lake Titicaca. These events have been detected by the Bolivian seismic network and two infrasound arrays operating for the Comprehensive Nuclear-Test-Ban Treaty Organization, situated at about 80 and 1620 km from the crater. The localization and origin time computed with the seismic records are consistent with the reported impact. The entry elevation and azimuthal angles of the trajectory are estimated from the observed signal time sequences and backazimuths. From the crater diameter and the airwave amplitudes, the kinetic energy, mass and explosive energy are calculated. Using the estimated velocity of the meteoroid and similarity criteria between orbital elements, an association with possible parent asteroids is attempted. The favorable setting of this event provides a unique opportunity to evaluate physical and kinematic parameters of the object that generated the first actual terrestrial meteorite impact seismically recorded.

A key component in seismic hazard assessment is the estimation of ground motion for hard rock sites, either for applications to installations built on this site category, or as an input motion for site response computation. Empirical ground motion prediction equations (GMPEs) are the traditional basis for estimating ground motion while V S30 is the basis to account for site conditions. As current GMPEs are poorly constrained for V S30 larger than 1000 m/s, the presently used approach for estimating hazard on hard rock sites consists of ''host-to-target'' adjustment techniques based on V S30 and j 0 values. The present study investigates alternative methods on the basis of a KiK-net dataset corresponding to stiff and rocky sites with 500 \ V S30 \ 1350 m/s. The existence of sensor pairs (one at the surface and one in depth) and the availability of P-and S-wave velocity profiles allow deriving two ''virtual'' datasets associated to outcropping hard rock sites with V S in the range [1000, 3000] m/s with two independent corrections: 1/down-hole recordings modified from withinThe following softwares are employed in this study: 1) the one written by J.-C. Gariel and P.-Y.Bard of the 1D reflectivity approach (Kennett 1974); 2) the site_amp v.5.6 program package provided by Dave Boore (U.S. Geological Survey); and the pikwin software developed by Perron et al. (2017). DOI 10.1007/s10518-017-0142-6 motion to outcropping motion with a depth correction factor, 2/surface recordings deconvolved from their specific site response derived through 1D simulation. GMPEs with simple functional forms are then developed, including a V S30 site term. They lead to consistent and robust hard-rock motion estimates, which prove to be significantly lower than host-to-target adjustment predictions. The difference can reach a factor up to 3-4 beyond 5 Hz for very hard-rock, but decreases for decreasing frequency until vanishing below 2 Hz. Electronic supplementary materialBull Earthquake Eng