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An Mw 7.5 earthquake struck Palu in the northern coast of Sulawesi island, Indonesia, on 28 September 2018. Its focal mechanism was determined to be a left‐lateral strike‐slip fault, which is generally expected to not produce a tsunami. However, a large tsunami with runup heights of more than 6 m was observed along the coast of Palu city. Here, we show a complex triggering supershear source model as determined by teleseismic waveform inversion. Three asperities with different slip characteristics were found on the 120‐kilometer‐long rupture zone. Significant triggering rupture with a supershear speed was observed south of the epicenter, which was just beneath Palu city. This special rupture process can cause a strong directivity effect that produced anomalously large ground shaking with nonlinear effects in Palu area. The coseismic deformation determined from the inverted source model showed large horizontal displacements. These horizontal movements combined with complex bathymetry and topography could have pushed seawater to generate a tsunami even though the Palu earthquake was a strike‐slip event.

The 5 February 2016, Meinong, Taiwan, earthquake brought extensive damage to nearby cities with significant pulse‐like velocity ground motions. In addition to the spatial slip distribution determination using filtered strong‐motion data, we show that, with the advantage of the densely distributed seismic network as a seismic array, we can project the earthquake sources (asperities) directly using nearly unfiltered data, which is crucial to the understanding of the generation of the pulse‐like velocity ground motions. We recognize that the moderate but damaging M_L 6.6 Meinong earthquake was a composite of an M_w 5.5 foreshock and an M_w 6.18 mainshock with a 1.8–5.0 s time delay. The foreshock occurred at the hypocenter reported by the official agency, followed by the mainshock with a centroid located at 12.3 km to the north‐northwest of the hypocenter and at a depth of 15 km. This foreshock–mainshock composition is not distinguishable in the finite‐fault inversion because it filtered the seismic data to low frequencies. Our results show that the pulse‐like velocity ground motions are mainly attributed to the source of mainshock with its directivity and site effects, resulting in the disastrous damages in the city of Tainan. Although finite‐fault inversion using filtered seismic data for spatial slip distribution on the fault has been a classic procedure in understanding earthquake rupture processes, using a dense seismic network as a seismic array for unfiltered records helps us delineate the earthquake sources directly and provide more delicate information for future understanding of earthquake source complexity.

On 6 February 2016, an M L 6.6 earthquake occurred in the Meinong area of southern Taiwan, causing anomalously large ground shaking. In this study, a joint source inversion was performed to understand the rupture process of this event and to identify how the anomalous strong motion was produced. The results show that the rupture process of this event was complex; at least two asperities were identified on the fault plane. The rupture mainly developed in the down‐dip direction and propagated toward the northwest. Results from a 3D wave propagation simulation further indicate that the strong ground shaking observed in southwest Taiwan was caused by a combination of three effects: (1) rupture directivity, (2) source radiation pattern, and (3) sedimentary amplification. The results demonstrate that constructive source rupture and wave propagation effects due to a moderate earthquake can cause anomalously strong ground motion and serious seismic hazards in nearby densely populated areas.

The Mw8.4 Illapel earthquake occurred on 16 September was the largest global event in 2015. This earthquake was not unexpected because the hypocenter was located in a seismic gap of the Peru-Chile subduction zone. However, the source model derived from 3-D spectral-element inversion of teleseismic waves reveals a distinct two-stage rupture process with completely different slip characteristics as a composite megathrust event. The two stages were temporally separated. Rupture in the first stage, with a moment magnitude of Mw8.32, built up energetically from the deeper locked zone and propagated in the updip direction toward the trench. Subsequently, the rupture of the second stage, with a magnitude of Mw8.08, mainly occurred in the shallow subduction zone with atypical repeating slip behavior. The unique spatial-temporal rupture evolution presented in this source model is key to further in-depth studies of earthquake physics and source dynamics in subduction systems.

The interaction between two flipping subduction systems shapes the complicated lithospheric structures and dynamics around the Taiwan region. Whether and in what form the Eurasian Plate subducts/deforms under Taiwan Island is critical to the debate of tectonic models. Although an east dipping high-velocity anomaly down to a depth below 200 km has been reported previously, its detailed morphology remains uncertain and leads to different interpretations. With a two-step strategy of nonlinear joint inversion, the slab images of the Eurasian Plate were retrieved in a geometry that is hyperthin in the south, becoming massive and steeper in the central, and severely deformed in the north. The possible depth and dimension of a slab break were also investigated through synthetic tests of whether the slab had torn. Moreover, the slab deflection found at ~23.2°N latitude seems to correspond to where the nonvolcanic tremors and recent NW-SE striking structures have occurred in southern Taiwan.

The Taiwan orogen sitting at the pre-rifted Eurasian margin and bracketed by two sub-orthogonal subduction systems is subject to complicated geotectonics, motivating numerous seismic tomographic studies in local and regional scale. Most of them obtained P-wave velocities (Vp), or with Vp/Vs ratio jointly, but few were for S-wave velocities (Vs). With unprecedented amount of S-wave data, in this study a new set of well-tuned Vp, Vs, and Vp/Vs models were determined by an elaborate joint-inversion scheme, integrating the data of P- and S-wave travel times, S–P times, and the borehole logging data (for near-surface correction) into one system. This allowed us to revisit the subduction-collision process in detail by comparing Vp, Vs, and Vp/Vs ratio simultaneously. With enhanced slab imaging of Philippine Sea Plate (PSP) under northeast Taiwan, we are able to discriminate the plausible missing Luzon forearc basement along the plate boundary and propose a “skateboarding” edge model, in which the westernmost PSP rides on the east-subducted forearc basement and subducts northward underneath the Eurasian lithosphere. The underlain forearc basement along with the PSP subduction then results in the anomalous shallow double seismic zone observed only near Taiwan Island. Meanwhile, at around 121°E the north-subducting PSP seems dipping west to collide with the deep Eurasian lithosphere, shaping an irregular corner wedge structure. In addition, we evaluate our model with previous ones by waveform modeling approach and show the current performance of travel-time tomography in Taiwan region.

The 2011 Tohoku earthquake ( M 9.0) caused significant hazards including strong ground motion, coseismic ground deformation, and tsunamis. For a deeper understanding of these phenomena, we conducted a large‐scale, parallel computer simulation by means of the finite‐difference method (FDM) with newly developed tsunami‐coupled equations of motion. This method is based on the equations of motion for an elastic medium, treating seawater as elastic material having zero S ‐wave velocity. Tsunami waves are included by taking into account gravity and their equilibrium with the pressure gradient. An effective method of FDM simulation using the state‐of‐the‐art massively parallelized K computer is also studied. With the use of a 3D layered velocity structure that includes topography and bathymetry, basement structure, Moho depth, and plate boundaries, and use of the appropriate source‐rupture model based on joint inversion of seismic waves and geodetic observations, the simulated seismic waves demonstrate anomalous seismic‐wave propagation by the thick 3D basin structure inland. We also found that the sea column acts as a strong absorber of seismic waves for shallow up‐dip slip. On the ocean side, coseismic deformation and tsunamis are dynamically generated in this simulation. Tsunami attacks on the subsided Pacific coast are simulated without any additional assumptions. We also modeled the tsunami and seismic records of ocean‐bottom pressure gauges above the fault. Because sea‐bottom tsunami and seismic observation is powerful but very complex, recording both seismic and tsunami waves, the use of these coupled numerical simulations has great potential for resolving complex source fault rupture processes in a 3D heterogeneous structure. Online Material: Mpeg movies of fault slip, seismic‐wave propagation, seafloor and ground displacement, and tsunamic propagation.

Seismic data collected during explosion experiments performed as part of the TAiwan Integrated GEodynamics Research (TAIGER) project provide an excellent opportunity to obtain high‐resolution images of the structure of the crust and upper mantle beneath Taiwan. The most significant feature observed at near‐source stations located on the western coastal plain in Taiwan is high‐energy later arrivals. These high‐amplitude multiples almost completely mask the lower‐amplitude signals (seismic refraction and wide‐angle reflection) from the deep crust. The later arrivals are identified as free‐surface‐reflected multiples. The nature and generation of these high‐energy, multiple diving waves are demonstrated using synthetic examples. Their generation requires the presence of a steep velocity gradient in the shallow crust. A detailed analysis of the observation data provided information on the velocity gradients in this region. An accurate layer‐velocity model, including the boundary orientation and its depth, and velocity gradient, was constructed based on a 1D waveform simulation and 2D seismic raytracing modeling for travel times. The present results indicate that the thick sediment in the survey area dips shallowly to the east, has a surface P ‐wave velocity of ![Graphic][1] , and an average velocity gradient of about 0.72/s from the surface to 3.0‐km depth. The thick sediment of the 2D model shows lateral variations in velocity gradient, increasing from west to east. This velocity model may provide useful information for future data processing to reduce multiple diving waves with the aim of enhancing the deep‐surface refraction/reflection signal. The velocity gradient calculated for the thick sediment of the western coastal plain may require a revision of the regional seismic velocity model developed for southwestern Taiwan, to improve the accuracy of regional hypocenter determinations, and to predict the strong ground motions produced by large earthquakes beneath this region. [1]: /embed/inline-graphic-1.gif

article i nfo Article history: We estimated the source rupture of the 2008 Wenchuan Earthquake (Ms 8), China, based on a back- projection of seismic waves to their source plane, using data from regional broadband arrays in Taiwan and northern Vietnam. Observations from these arrays, located at different azimuths, were processed to eval- uate the spatio-temporal rupture behavior of the fault. The seismic energy spot converted from windowed array waveforms was back-projected to the rupture plane of the earthquake, to image the instantaneous slip on the fault plane. Rupture processes were reconstructed based on the imaged time-dependent seismic energy radiating from the earthquake fault plane. The high station density of both arrays enabled a detailed examination of the rupture processes. The results indicate that the 2008 Wenchuan Earthquake had a rupture duration of approximately 100 s, with major asperities radiating energy at 50 s after the initiation of rupture. The location of asperities is in good agreement with sections of the earthquake fault along which major dam- age occurred, such as along the Yingxiu-Beichuan Fault. The radiated seismic energy shows a complex spatial distribution on the fault plane. Our analysis indicates that the rupture initiated at the epicenter and extended to the northeast for approximately 280 km. The average rupture velocity of this earthquake was approxi- mately 2.8 km/s.

The southern Ryukyus represents an area where different tectonic stress regimes result in high seismicity and increased seismic hazard for nearby areas such as Taiwan. On 18 December 2001 at 04:03 (GMT) a strong earthquake (Mw 6.8) occurred in the forearc area of the southern Ryukyu subduction zone. Revised moment tensor solutions published by GCMT and BATS groups show a normal faulting mechanism with some strike-slip component and also point to a shallow focal depth (∼12 km). We use arrival times picked at both Taiwanese and Japanese stations along with a 3D geo-realistic a priori velocity model in order to obtain accurate absolute locations for the mainshock and 153 of its aftershocks. Locations are derived by using the Maximum intersection (MAXI) algorithm which has been used in many previous seismicity studies in the southern Ryukyus. These improved locations indicate that the mainshock was caused by the failure of a NE–SW oriented fault that extends from the edge of the Nanao forearc sedimentary basin to the Ryukyu arc basement. Far-field P and SH waveforms of the mainshock recorded at stations surrounding the source and at distances 30–100°, were inverted for the purpose of investigating its rupture process. A non-negative least-squares inversion technique utilizing multiple time windows was used to derive the spatio-temporal slip distribution. The preferred slip distribution model shows that there is one large area of high slip (∼0.9 m) at 5–15 km depth that essentially represents the crystalline rocks of the Ryukyu arc basement. Another smaller area with lower slip (∼0.4 m) extends at 10–15 km depth beneath the Nanao basin. Most aftershocks are located in areas of low slip (

On 8 June 2008 at 12:25 (GMT) an M w 6.4 strong earthquake occurred in the area of northwest Peloponnese, western Greece, causing the death of two people and extensive damage to the surrounding area. The main event and its aftershocks were recorded by one nationwide and three regional networks equipped with three-component broadband seismometers. Initial locations of the earthquake sequence comprising 438 aftershocks showed a linear northeast–southwest trend and that the mainshock was located at 22 km depth. After the relocation using catalog and differential travel times, most events form three distinct clusters at depths 15–25 km. Moment tensor solutions for the main event and its largest aftershocks exhibited a pure strike-slip mechanism with one nodal plane orientated northeast–southwest in accordance with the relocated seismicity. A parallel, nonnegative least-squares inversion technique utilizing multiple-time windows was used to derive the spatiotemporal slip distribution of the main event. The resulting slip distribution model revealed a large slip patch (maximum slip ∼150 cm) between 10 and 20 km depth at the northeast part of the fault that also coincides with the area that suffered most of the damage. Another patch exhibiting smaller amounts of slip (20–50 cm) is located to the southwest direction at the same depth range, and smaller patches exist at 25–30 km depth. Most aftershocks are located in areas of low slip (

On 8 January 2006 at 11:34 (GMT) a strong (Mw 6.7) subcrustal earthquake occurred near Kythira island in southern Greece, causing damage to the surrounding area while the shock was also felt in most of the eastern Mediterranean. The event and its aftershocks were recorded by a regional network of 31 stations equipped with three-component broad-band seismometers that cover most parts of the Greek region. Initial locations of the earthquake sequence showed a diffuse pattern, therefore catalog and cross-correlation differential travel times were input to a shrinking grid-search relocation algorithm in order to obtain accurate relative locations. After this relocation most aftershocks form a tight cluster around the mainshock at depths between 44 and 53 km. Subsequently, waveforms from 12 stations giving the best possible azimuthal coverage around the Kythira event were inverted in order to investigate its source process. A parallel, non-negative least-squares inversion technique utilizing multiple time windows was used to derive the spatiotemporal slip distribution. The fault surface was parameterized by subfaults of 3 km × 3 km size covering a length and down-dip width of 91 and 100 km, respectively. Inversion results indicate that the fault plane is probably the one dipping towards SE. The slip distribution model showed that there are two areas of large slip (∼60 cm), the largest extending between 38 and 80 km depth and a smaller one at depths 65–82 km. The moment rate function consists of a large initial peak with a duration of about 11 s followed by a number of smaller peaks, probably due to coseismic slip on some of the subfaults. Furthermore, the hypocenters of the relocated aftershocks coincide with the areas of minimum slip (

Topography influences ground motion and, in general, increases the amplitude of shaking at mountain tops and ridges, whereas valleys have reduced ground motions, as is observed from data recorded during and after real earthquakes and from numerical simulations. However, recent publications have focused mainly on the implications for ground motion in the mountainous regions themselves, whereas the impact on surrounding low-lying areas has received less attention. Here, we develop a new spectral-element mesh implementation to accommodate realistic topography as well as the complex shape of the Taipei sedimentary basin, which is located close to the Central Mountain Range in northern Taiwan. Spectral-element numerical simulations indicate that high-resolution topography can change peak ground velocity (PGV) values in mountainous areas by ±50% compared to a half-space response. We further demonstrate that large-scale topography can affect the propagation of seismic waves in nearby areas. For example, if a shallow earthquake occurs in the I-Lan region of Taiwan, the Central Mountain Range will significantly scatter the surface waves and will in turn reduce the amplitude of ground motion in the Taipei basin. However, as the hypocenter moves deeper, topography scatters body waves, which subsequently propagate as surface waves into the basin. These waves continue to interact with the basin and the surrounding mountains, finally resulting in complex amplification patterns in Taipei City, with an overall PGV increase of more than 50%. For realistic subduction zone earthquake scenarios off the northeast coast of Taiwan, the effects of topography on ground motion in both the mountains and the Taipei basin vary and depend on the rupture process. The complex interactions that can occur between mountains and surrounding areas, especially sedimentary basins, illustrate the fact that topography should be taken into account when assessing seismic hazard.

We perform full elastic wave-field simulations within the Taipei basin by using a three-dimensional (3D) discontinuous finite-difference method. The 3D Taipei basin model is determined from a seismic reflection study. Two major subsurfaces, the Songshan formation (surface soil layer) and the basin basement, are constituted in the model. A parallel-based composite grid technique, a containing scalene grid and a discontinuous grid, is developed in this study to deal with the possible numerical prob- lem of thin depth and low velocity of the Songshan formation. Taking advantage of the composite grid, the resolution of the subsurface structure can be reached to 20 m, and a higher frequency (up to 3 Hz) of the synthetic waveform can be achieved. In our strong ground motion simulations, we assume a constant velocity in each subsurface. Three different types of models are considered in the study: the Songshan formation with a basement structure model, a basin basement model, and a layered half-space model. Results indicate that only the model with both the Songshan formation and the basement structure can produce the apparent basin amplification effects. First, the surface wave generated after the primary S wave is trapped at the shallow part of the basin. Then, when the wave propagates through the deepest part of the basin, most of the energy is reflected from the boundary and focused back into the basin. In addi- tion, part of the seismic wavefront turns and follows the shallow basin edge resulting in further amplification. Our study indicates that the complex Taipei basin geometry and fairly low velocity of the Songshan formation dominate the amplification and wave propagation behavior that result in extraordinary strong shaking patterns in the Taipei metropolitan region.

We investigated the fault geometry effects and the corresponding coseismic slip distribution using various proposed earthquake fault models for the Chi-Chi earthquake of 21 September 1999. The types of fault geometries are threefold: a simple planar fault plane, a two segmented planar fault plane and a three dimensional (3D) curved fault surface rupture propagation model. We derived the estimated spatial slip distribution from an inversion analysis of GPS coseismic displacement data and show that the 3D fault model is the preferred solution. The simple and segmented fault models lead to significant artificial slip distributions associated with the pre-defined fault geometry and the spatial distribution of GPS stations. The spatial distribution of coseismic slip deduced from the 3D fault model has three observable features: (1) the overall slip is concentrated at depth of less than 12 km, which may well correspond to a shallow-dipping detachment; (2) the maximum slip of about 10 m is located 45 km to the north of the epicenter; and (3) the slip vector is dominated by the dip-slip component. In addition, the results from the inversion of GPS data are consistent with those from the inversion analysis of teleseismic broadband data. A resolution analysis, further, demonstrates that the results are highly correlated with field GPS data studies when we used synthetic test data. The inversion of spatially distributed GPS data is highly sensitive to fault geometry. We conclude that the use of the 3D fault model is not only necessary but also certainly competent enough to well explain the inferred slip style and the observed static coseismic displacements. D 2005 Elsevier B.V. All rights reserved.

We investigated the rupture process of the 1999 Chi-Chi, Taiwan, earth- quake, using high-quality near-source strong-motion records, broadband teleseismic displacement waveforms, and well-distributed Global Positioning System (GPS) data. The near-source strong-motion displacement waveforms recorded significant static offsets of up to 8 m. The teleseismic displacement records show a significant pulse with duration of about 18 to 20 sec. Taking into account the surface displacements observed along the Chelungpu fault, we considered two fault geometries: a single planar fault and a two-segment fault with a northeast-striking section near the north- ern end. Using the finite-fault model with variable slip vectors, we derived two models of the temporal and spatial slip distribution of the earthquake. The GPS data provided good surface displacement constraints for the slip-distribution determina- tion. The spatial slip distribution is generally consistent with field observations. The results for the simple fault model show a large asperity located in the region about 25 to 55 km north of the hypocenter with maximum slip of about 15 m. When we use the two-segment model, the asperity further extends to the region where the fault bends toward the northeast with a maximum slip of up to 20 m. A large amount of right-lateral slip beneath station TCU068 is necessary to explain its observed large west movement. It implies a local converging slip at the corner where the fault bends to the northeast. The slip amplitude near the hypocenter is about 3 to 6 m. The seismic moments determined from the various data sets are within the range of 2 to 4 10 27 dyne cm. Most of the slip concentrated at shallow depths (less than 10 km). The total rupture duration is about 28 sec, and the rupture velocity is 75% to 80% of the shear-wave velocity. The slip vector shows a clockwise rotation during the fault rupture. The static stress drop of the large asperity region is comparable with the dynamic stress drop, as observed directly from the slip velocity at the station near the large slip region.

The teleseismic waveforms of the MW7.6 September 20, 1999 Chi-Chi earthquake were examined to obtain the quick information on the fault rupture process. The deconvolution results show the fault ruptured from south to the north, and revealed the west movement of the hanging wall to the footwall on the eastern dipping plane. The spatial slip distribution shows that the earthquake was mainly composed by a large asperity with a dimension of about 45km × 15km. The maximum slip was about 8 m located at about 45 km to the north of the epicenter. The slip distributions obtained in this study have a good agreement with the observed surface breaks. The comparable static and the dynamic stress drops of about 11 Mpa in the large slip region indicate that the melting/fluid pressurization might have taken place in this earthquake. It reduces the dynamic friction and results in the large slip observed.

[1] The repetition of slip during rupture process of earthquake is a debate issue which had never been confirmed clearly in the past big events due to the lack of dense near-field observations and limited resolution in time of source model. The 2011 M9.0 Tohoku-Oki earthquake generated a wealth seismic records which provided us an unprecedented opportunity to study the rupture evolution of giant earthquake at a high spatio-temporal resolution. Here we use teleseismic, local strong motion and near-field coseismic geodetic data to investigate the source rupture process of this event based on the parallel inversion technique. The results reveal a broad slip zone with remarkable large scale repeating slip during the earthquake. The inverted source model shows several time periods of energy release with three main peaks. These energy bursts and temporal rupture snapshots suggest repetition of a large scale slip on the biggest asperity. This rupture behavior resulted in >50 m slips on the slip zone and prolonged the entire rupture process for a long duration of ∼160 seconds. The proposed source model is in a good agreement with the aftershock distribution and can interpret the characteristics of local strong motions. Further investigations of repeating slip during this event are crucial which will deeply transform earthquake science from dynamic point of view.

We use the spectral-element method to simulate strong ground motion throughout the Taipei metropolitan area. Mesh generation for the Taipei basin poses two main challenges: (1) the basin is surrounded by steep mountains, and (2) the city is located on top of a shallow, low-wave-speed sedimentary basin. To accommodate the steep and rapidly varying topography, we introduce a thin high-resolution mesh layer near the surface. The mesh for the shallow sedimentary basin is adjusted to honor its complex geometry and sharp lateral wave-speed contrasts. Variations in Moho thickness beneath Northern Taiwan are also incorporated in the mesh. Spectral-element simulations show that ground motion in the Taipei metropolitan region is strongly affected by the geometry of the basin and the surrounding mountains. The amplification of ground motion is mainly controlled by basin depth and shallow shear-wave speeds, although surface topography also serves to amplify and prolong seismic shaking.

[1] We simulate the strong ground motion of 1999 Chi-Chi, Taiwan earthquake (Mw = 7.6) by considering a three-dimensional source rupture model in a full waveform three-dimensional wave propagation study. The strong ground motion records during the 1999 Chi-Chi earthquake show various characteristics at different sites in Taiwan. We adopt a three-dimensional source model derived from an inversion study with identical path effects as considered in this three-dimensional forward study. Comparisons between the simulation results and observed waveforms from dense island-wide strong motion stations demonstrate that the fault geometry, lateral velocity variation, and complex source rupture process greatly influence the distribution of strong ground shaking. The simulation has reproduced the heavy damage area that is mainly concentrated in the hanging wall, especially close to the surface break of the Chelungpu fault. The source directivity effect is also reproduced and shows serious shaking along the northward rupture direction. Low-velocity material in the shallow part of the Western Plain is found to generate significantly amplified ground motions. In the Central Range, the shaking is relatively weak owing to the energy radiation characteristics of a low-angle thrust of the Chelungpu faulting system. The wavefield is then amplified by a high-velocity gradient under the Coastal Range. Our simulation results in the frequency range of 0.01–0.5 Hz give good agreement with the extensive strong motion observations of the Chi-Chi earthquake. We find that adequate source representation, good three-dimensional crustal velocity structures, and careful numerical work are necessary to make the ground motion prediction feasible.

[1] We inverted the high-resolution spatiotemporal slip distribution of the 21 September 1999 Chi-Chi, Taiwan, earthquake utilizing data from densely distributed island-wide strong motion stations for a three-dimensional (3-D) fault geometry, and 3-D Green's functions calculations based upon parallel nonnegative least squares inversion. The 3-D fault geometry, consistent with high-resolution reflection profile, is determined from GPS inversion and aftershocks distribution. This 3-D fault model presents the dip angle gradually becoming shallower from south to north along the fault and near flat at the deeper portion of the fault. The 3-D Green's functions are calculated through numerical wavefield simulation from three-dimensional heterogeneous velocity structure derived from tomography studies. The Green's functions show significant azimuthal variations and suggest the necessity of lateral heterogeneity in velocity structure. Considering complex fault geometry and Green's functions in full 3-D scale, we invert the spatial/temporal slip distribution of the 1999 Chi-Chi earthquake using the best available and most densely populated strong motion waveform data. We perform the inversion under a parallel environment utilizing multiple-time window to manage the large data volume and source parameters. Results indicate that most slip occurred at the shallower portion of the fault above the decollement. Two major asperities are found, one in the middle of the fault and another one at the northern portion of the fault near the bend in the fault trace. The slip in the southern portion of the fault shows a relatively low slip rate with longer time duration, while the slip in the northern portion of the fault shows a large slip rate with shorter time duration. The synthetics explain the observations well for the island-wide distributed strong motion stations. This comprehensive study emphasizes the importance of realistic fault geometry, 3-D Green's functions, and parallel inversion technique in correctly accounting for both the detailed source rupture process and its relationship with the strong ground motion of this intense earthquake.

This short note describes the results in computer readable files from our article, “Spatial and Temporal Distribution of Slip for the 1999 Chi-Chi, Taiwan Earthquake”. We investigated the rupture process of the 1999 Chi-Chi, Taiwan, earthquake using 21 three-component near-source strong-motion records, 22 P -wave broadband teleseismic displacement waveforms, and 131 well-distributed GPS data points. The strong-motion records were provided by the Seismology Center, Central Weather Bureau (CWB), Taipei, Taiwan, distributed on CD-ROM on December 1999. The broadband data were provided by IRIS, and the GPS data was provided by Institute of Earth Sciences, Academia Sinica. Two fault geometries are considered in the calculations: a single planar fault and two-segment fault with a northeast striking section near the northern end. There are three files …