Studies of Earthquake Energies in Taiwan: A Review

Wang, Jeen-Hwa

doi:10.3319/tao.2015.10.13.01(t)

Cited by 4 publications

(2 citation statements)

References 80 publications

(183 reference statements)

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“…The seismic moment is estimated at 3.046 × 10 20 N•m by the USGS with a mean slip of 2-3 m. Thousands of people were injured or killed, and many infrastructures were destroyed. During the three months following the event [2], thousands of aftershocks occurred including six with a magnitude greater than 6.5, starting at the north and migrating downward and southward of the main event [3]. As presented in Reference [4], it is interesting to look at the seismicity (Figure 1) and its implications for the tectonics-two NW-SE patterns, one starting at the north of the fault and one at the south end between the Luliao and Tachienshan faults are clearly visible and point out the impact of this event on nearby faults such as the Luliao fault that most probably was activated during the Chi-Chi event.…”

Section: Introductionmentioning

confidence: 99%

Joint Inversion of Geodetic Observations and Relative Weighting—The 1999 Mw 7.6 Chi-Chi Earthquake Revisited

Roger

Clarke

et al. 2020

Remote Sensing

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The Mw 7.6 Chi-Chi earthquake struck central western Taiwan in 1999. The rupture was complex with several dislocations along the 100-km long Chelungpu thrust fault. Revisiting this earthquake is a challenge, as the precision and coverage of the data sets available are quite poor. Furthermore, the topographic and vegetation coverage complexity of the area prevents coherent radar images. In this paper, radar and optical images, and terrestrial geodetic measurements, were utilised to study the fault. The Particle Swarm Optimization and Okada Inversion (PSOKINV) geodetic inversion package was used with the generalized Akaike’s Bayesian Information Criterion (gABIC) to precisely determine the slip distribution and relative weighting of datasets. Differences in results using the data sets jointly or separately (e.g., under-estimation due to InSAR, inconsistencies in SPOT offsets, smoother slip distribution with gABIC weighting) are observable. Most of the energy was released in the northern part of the fault, where the strike veers toward the east, and mainly at depths less than 4 km. The PSOKINV-gABIC approach is viable for the study of complicated cases such as the Chi-Chi earthquake and can significantly benefit the weight determination and physical realism of the fault geometry.

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Section: Introductionmentioning

confidence: 99%

Joint Inversion of Geodetic Observations and Relative Weighting—The 1999 Mw 7.6 Chi-Chi Earthquake Revisited

Roger

Clarke

et al. 2020

Remote Sensing

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“…Up to date, only Shaw [1993] studied this problem using a modified version of the one-dimensional dynamical spring-slider mode (abbreviated by the 1-D BK model hereafter) proposed by Burridge and Knopoff [1967]. Meanwhile, friction controls the rupture processes of an earthquake [e.g., Nur 1978, Knopoff et al 1992, Rice 1993, Shaw 1993, Wang 1996, 1997, 2006a, 2007, 2008, 2009, 2016. Shaw [1993] considered velocity-weakening friction, as shown below, suggested by Carlson and Langer [1989].…”

Section: Introductionmentioning

confidence: 99%

A dynamical study of frictional effect on scaling of earthquake source displacement spectra

Jeen-Hwa Wang

2016

Annals of Geophysics

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The scaling of earthquake source displacement spectra is analytically studied based on the continuous form of one-dimensional dynamical spring-slider model in the presence of either linearly slip-weakening friction or linearly velocity-weakening friction. The main parameters of the model are the natural angular frequency, wo, and the (dimensionless) decreasing rate, D, of friction with slip (or the characteristic displacement) for slip-weakening friction as well as the (dimensionless) decreasing rate, u, of friction with velocity (or the characteristic velocity) for velocity-weakening friction. The analytic solution includes the complementary and particular parts. The former shows the travelling wave and the latter denotes vibrations at a site. The complementary solution exhibits w-1 scaling in the whole range of w for both friction laws. For the particular solution, slip-weakening friction results in spectral amplitudes only at three values of w. For velocity-weakening friction with u>0.5, the log-log plot of spectral amplitude versus w exhibits almost w0 scaling when w is lower than the corner angular frequency, wc, which is independent on u and increases with wo. When w>wc, the spectral amplitude monotonically decreases with w following a line with a slope value of -1, which is the scaling exponent.

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Can the Thermal Infrared Radiation Anomalies Reported Before Earthquakes be a Precursor?

Wang

2024

J. Earthquake and Tsunami

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Twenty-seven earthquakes in Taiwan with local magnitudes [Formula: see text] and focal depths d = 8.0−215.8[Formula: see text]km were preceded by thermal infrared radiation (TIR) anomalies. The data are taken as an example to investigate the mechanisms of generating the TIR and to examine whether the TIR anomalies can be considered as a precursor or not. Let [Formula: see text] and [Formula: see text] be the largest number of days before forthcoming earthquakes when the anomalies are observed in the day-time and the night-time, respectively. The precursor time, T, for an event, is the larger value of [Formula: see text] and [Formula: see text]. The plots of both T vs. [Formula: see text] and [Formula: see text] vs. [Formula: see text] are scattered. Regardless of two data points with abnormally large [Formula: see text] values, it seems able to recognize a positive correlation between [Formula: see text] and [Formula: see text]. Among the 27 earthquakes, 8 events were proceeded by Rn concentration changes whose precursor times are [Formula: see text] days. For most of the eight events, [Formula: see text] is much longer than either [Formula: see text] or [Formula: see text]. Hence, the model of outflow of gases from the depths to the ground surface for describing the Rn concentration changes cannot interpret the TIR anomalies. Based on rock mechanics, the temperature rise, [Formula: see text], is generated by frictional heating due to preseismic slip. That the TIR anomalies discontinuously appeared before earthquakes and the occurrence times vary for different events is inconsistent with the processes of generation of frictional heating caused by preseismic slip on a few shallow faults in the source areas before forthcoming earthquakes. Since theoretical results and observations are not consistent, the answer to the title of this study is negative.

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Studies of Earthquake Energies in Taiwan: A Review

Cited by 4 publications

References 80 publications

Joint Inversion of Geodetic Observations and Relative Weighting—The 1999 Mw 7.6 Chi-Chi Earthquake Revisited

Joint Inversion of Geodetic Observations and Relative Weighting—The 1999 Mw 7.6 Chi-Chi Earthquake Revisited

A dynamical study of frictional effect on scaling of earthquake source displacement spectra

Can the Thermal Infrared Radiation Anomalies Reported Before Earthquakes be a Precursor?

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