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The devastating earthquake of 2015 in Nepal overwhelmed the Nepal government, which resulted in the government seeking help from the international community. The call from the Nepal government was responded to quickly by many countries. While the government accepted the help from far countries, the Nepal government rejected the humanitarian aid offered by Taiwan saying that Nepal only takes such aid from its neighboring countries. This paper examines the reasons behind the aid rejection of Taiwan by Nepal and tries to answer what could have happened if it was accepted. Though Nepal is one of the Least Developed countries, even during the disaster time, the aid was rejected. The paper concludes that, even during the most crucial time, there is politics in accepting aid. Nepal's rejection of Taiwan's aid was because of the pressure to obey the diplomatic relation with China, as Nepal is dependent on China but not on Taiwan. [ABSTRACT FROM AUTHOR]

This paper reports the bridge damage in the Chi Chi earthquake. Damage to bridge structures may occur in the superstructure, the substructure, or the approaches. Typical types of damage are discussed and illustrated in this paper. A review of the design specifications in Taiwan is also presented to give the background on the seismic design of highway bridges in Taiwan. [ABSTRACT FROM AUTHOR]

Purpose |!|#8211; The purpose of this paper is to examine the effectiveness of building codes in earthquake risk mitigation in Taiwan. Design/methodology/approach |!|#8211; Using probabilistic risk analysis tools with available data, this study assesses the exceedance probability of extensive damage limit for general buildings in their 50-year useful lives. The buildings were classified into 15 categories according to their construction materials and building height. Then, the effects of construction materials, building height and construction years are detected. Findings |!|#8211; The exceedance probabilities of extensive damage limit for all of the investigated buildings in their 50-year useful lives are on the order of 10-2. The effect of construction materials and building height on seismic risk of buildings is decreasing with the development of a seismic design code. Significant discrepancy of seismic risk still exists among some buildings. Research limitations/implications |!|#8211; Seismic risk analysis requires quite restrictive statistical idealizations for the relevant probabilistic terms in the mathematical formulation. The problem of imperfect simplification and lack of sufficient empirical data has shown the research needs for improvements of seismic risk assessment. The questions of what constitutes acceptable risk for various performance levels and how safe is safe enough remain context-specific. Originality/value |!|#8211; Although probabilistic risk analysis provides a tool for quantifying the probability of structural failure, current earthquake-resistant design procedures do not relate performance levels to probability. The paper explores some probability information for current earthquake-resistant design for general buildings during their 50-year useful lives and the information may provide some valuable information for future code calibration. [ABSTRACT FROM AUTHOR]

The paper examines the motives and sources of satisfaction of 286 respondents relating to the 921 Earthquake Museum in Taichung, Taiwan. In concludes that income, age and education remain statistically significant determinants of at\titudes, and notes the existence of four clusters derived from k-means analysis but supported by a cross-tabulation of cluster types and categories derived from themes identified in responses to open-ended questions. The paper lends some support to the continuum of the authentic to 'pure essentialism' while arguing that the latter is a logical corollary of the concept, but in practice will be rare. In that respect the Museum represents a negotiated essentialism in that the core of the Museum is the damaged school, but it has been sanitized. Reference is also made to differing concepts of museums and the literature relating to competing understandings of the roles of museums and why people visit them. [ABSTRACT FROM AUTHOR]

Seismic early warning has been very important and has become feasible in Taiwan. Perhaps because of the lack of quick and reliable estimations of the induced structural response, however, the triggering criteria of almost all of the existing earthquake protection or early warning systems in the world are merely based on the collected or estimated data of the ground motion, without any information regarding the structural response. This paper presents a methodology of generating quick seismic response estimations of a prestressed concrete (PC) bridge using artificial neural networks (ANNs), which may be incorporated in a seismic early warning system for the bridge. In the methodology ANNs were applied to model the critical structural response of a PC bridge subjected to earthquake excitation of various magnitudes along various directions. The objective was to implement a well-trained network that is capable of providing a quick prediction for the critical response of the target bridge. The well-known multilayer perception (MLP) networks with back propagation algorithm were employed. A simple augmented form of MLP that can be quantitatively determined was proposed. These networks were trained and tested based on the analytical data obtained from the nonlinear dynamic finite fiber element analyses of the target PC bridge. The augmented MLPs were found to be much more efficient than the MLPs in modeling the critical bending moments of the piers and girder of the PC bridge. [ABSTRACT FROM AUTHOR]

A disastrous earthquake struck central Taiwan at 01:47 a.m. September 21, 1999 (Taiwan local time). The Seismology Center of the Central Weather Bureau (CWB) determined the magnitude of this earthquake to be ML 7.3 (CWB) and MW 7.7 (Harvard CMT). The earthquake caused heavy casualties and structural damage to bridges and buildings. In the damaged areas, the only cable-stayed bridge, the Chi-Lu, was in the final stages of completion at the time of the earthquake. This bridge connected Chi-Chi to the small town of Lu-Ku across the Juoshuei River. Viaducts ran from both banks of the river to the ends of the cable-stayed bridge. The bridge, designed by T. Y. Lin International, was supported on a single pylon, which was connected to the center of the roadway by two rows of cables. In this paper, the damage suffered by the Chi-Lu bridge is reported. Severe damage occurred in the deck on the southern side of the bridge. Additional damage occurred in the pylon. Below the roadway, the pylon showed evidence of only minor cracking. However, above the roadway there was severe spalling of the cover and a crack extended upward nearly to the level of the lowest cables. The seismic performance of the bridge was evaluated by computer modeling. The damage predicted by the computational results was compared to that sustained by the bridge. The lessons learned from this study are described. [ABSTRACT FROM AUTHOR]

Background: Few studies have explored the field experiences and risk factors related to post-traumatic stress disorder (PTSD) among disaster rescue workers.Methods: A 6.4-magnitude earthquake struck southern Taiwan on February 6, 2016. A standardized, paper-based, self-administered survey questionnaire including demographic information, field experiences and the Post-Traumatic Stress Disorder Checklist (PCL) was conducted among emergency medical technicians (EMTs) one month after the earthquake. A multivariate regression model was used to analyze the associations between risk factors and the PCL. A two-sided p value less than 0.05 was considered statistically significant.Results: The survey response rate was 86.1% (447/519). The respondents who exceeded the cut-off points for the re-experience, avoidance, or hyperarousal domains were 11.8%, 2.7%, or 4.7%, respectively. A proportion of 12.7% of respondents met partial PTSD. The personality characteristics of anxiety (p < 0.001), perfectionism (p = 0.023) and introvert tendency (p = 0.002) were significantly correlated with partial PTSD. Emergency medical services (EMS) were significantly associated with partial PTSD than other main tasks (p < 0.001). The prevalence of partial PTSD was higher but was not significantly different in the groups of lower educational level, longer EMT careers, earlier arrival date, fewer field working hours, or managing dead people. Both univariate and multivariate logistic regression analyses showed that an anxious personality and EMS as the main task during the missions were significantly associated with PTSD risk.Conclusion: Not only personality characteristics but also the task components could alter the PTSD risks in disasters. A broad realization of these risks may improve the mental outcomes of disaster rescuers. [ABSTRACT FROM AUTHOR]

Engineering risk assessment is to estimate the structure's failure probability multiplied by its failure consequences. On the other hand, the analysis was sometimes performed on a more general basis, utilizing a few indicators to quantify relative risk levels for decision-making. On the basis of such a framework, this paper introduces a novel risk assessment on 18 active faults in Taiwan, considering the fault's location, earthquake size and return period from the literature. The result shows that the Chelungpu Fault in central Taiwan has the highest risk score among the 18 active faults, in contrast to the Hengchun Fault in southern Taiwan which has the lowest risk. Besides this, the 18 active faults in Taiwan were classified into four groups based on this risk assessment, and the classification could help the region's sustainable development against earthquake hazard. [ABSTRACT FROM AUTHOR]

Since the year 1973, more than 54,000 M ≥ 3.0 earthquakes have occurred around Taiwan, and their magnitude-frequency relationship was found following with the Gutenberg-Richter recurrence law with b value equal to 0.923 from the least-square calculation. However, using this b value with the McGuire-Arabasz algorithm results in some disagreement between observations and expectations in magnitude probability. This study introduces a simple approach to optimize the b value for better modeling of the magnitude probability, and its effectiveness is demonstrated in this paper. The result shows that the optimal b value can better model the observed magnitude distribution, compared with two customary methods. For example, given magnitude threshold = 5.0 and maximum magnitude = 8.0, the optimal b value of 0.835 is better than 0.923 from the least-square calculation and 0.913 from maximum likelihood estimation for simulating the earthquake's magnitude probability distribution around Taiwan. [ABSTRACT FROM AUTHOR]

The tourism industry is vulnerable to natural and human induced incidents such as terrorist attacks, political instability, flood and earthquakes. On September 21st 1999, a devastating earthquake struck Taiwan which caused severe damage to both local people and the tourism industry. This paper proposes an innovative integrated approach that could be adopted as a crisis management plan for Taiwan to restore its tourism industry. A thorough review of the crisis management literature is introduced and examined to generate an integrated crisis management framework. It is anticipated that this framework could accelerate tourism recovery by showing secure images for tourists, and hence the competitiveness of a tourist nation could be enhanced through sound crisis management practices. [ABSTRACT FROM AUTHOR]

Purpose — The aim of this article is to present a new, simple applicable method of inferring and assessing residential construction quality at an industry-wide level. Design/methodology/approach — Construction quality is measured using ratios of structural materials to production levels. Cement and reinforcing bar per 1,000m2 of residential floor space are the metrics, especially appropriate in Taiwan as new dwelling units (virtually all apartments and row houses) and all of reinforced concrete. Complementary measurements of quality for labour and non-structural construction material inputs were also made. Findings — The structural input and complementary measures indicate that the quality of Taiwanese residential construction declines dramatically and consistently at higher production levels. The implication is that dwelling units from the 1990s construction boom are especially at risk. Research limitations/implications — The methods cannot be used to identify specific buildings at risk. The methods are difficult to apply in situations where construction methods and residential types are heterogeneous. Practical implications - Construction quality can be monitored on a regular basis so industry-wide steps can be taken if quality declines appear. The evidence is consistent with Taiwan's sub-contractor network enabling rapid expansions and contractions at the expense of hidden quality failure. Originality/value - This paper provides information that could lead to much firmer regulatory systems, hence has the potential to help save lives and property. [ABSTRACT FROM AUTHOR]

This paper examines the impact of the Chi-Chi earthquake, which hit central Taiwan on September 21, 1999, on the quality of life among the elderly survivors. The 28-item Taiwanese-adapted brief version of the World Health Organization's quality of life questionnaire (WHOQOL-BREF) was used to measure quality of life in four domains: physical capacity, psychological well-being, social relationships, and environment. These measures were coincidently collected in a separate study from 368 subjects aged 65 and older in the affected area shortly before the earthquake. Of these subjects, 268 were interviewed in a follow-up assessment 12 months after the earthquake. Linear mixed models were applied to investigate how quality of life in each of the four domains changed from the pre-earthquake assessment to 12 months after the earthquake, and how these changes depended on the level of damage to residences. In conclusion, elderly survivors tended to report lower quality of life in physical capacity, psychological well-being, and environment 12 months after the earthquake than at the assessment prior to the earthquake, regardless of the level of damage to their residences during the earthquake. However, those whose residences completely collapsed during the earthquake reported a higher quality of life in social relationships while others reported the opposite. [ABSTRACT FROM AUTHOR]

In this paper, we study (1) the spatial anomalies and (2) the temporal anomalies of soil gas in northern Taiwan. The spatial anomalies of soil gas are related to tectonic faults, while the temporal anomalies of soil gas are associated with pre-earthquake activities. Detailed soil gas sampling was systematically performed, and the analysis of the collected gas species shows that high helium and nitrogen concentrations appear in samples from specific sites, which coincide with the structural setting of the area studied. This analysis indicates the possibility of using these soil gases to determine fault zones in the studied area. Based on the soil gas data, a station (Tapingti) for automatic soil gas monitoring was constructed on an appropriate site at the fault zone. Some anomalous high radon concentrations at certain times can be identified from the dataset, which was generated by the continuous monitoring of soil gas for over a year. Notably, many of these anomalies were observed several hours to a few days before the earthquakes (M L > 3) that occurred in northern Taiwan. By combining the information of epicenters and fault plane solutions of these earthquakes, we find that the shallow earthquakes (<15 km) were mainly strike-slip and normal-type earthquakes, and concentrated within a distance of 30 km to the monitoring site (Group A). The deep earthquakes (>20 km) were mainly thrust-type earthquakes and distributed in greater distances (>45 km) east of the monitoring site (Group B). Such focal mechanisms of earthquakes suggest an extensional and compressional structural domain in the continental crust for Group A and Group B earthquakes, respectively. It is suggested that the pre-earthquake activities associated with the seismicity of Group B may be transmitted along the major decollement in the region below the Tapingti station, leading to the observed soil gas enhancements. [ABSTRACT FROM AUTHOR]

The M w 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. [ABSTRACT FROM AUTHOR]

Earthquake early warning (EEW) has been implemented in several regions around the world. However, because of natural randomness and uncertainty, false alarm and missed alarm can be expected in EEW. The key scope of this study is to evaluate the reliability of an on-site EEW in Taiwan, by testing the system's algorithm with 17,836 earthquake data from 1999 to 2013. The analysis shows that the on-site EEW system, empirically speaking, should have a false-alarm probability of 2.5%, and a missed-alarm probability of 14.1%. Considering missed alarm should be more critical to EEW, a new algorithm that could reduce the system's missed-alarm occurrences to 6% is also discussed in this paper. [ABSTRACT FROM AUTHOR]

The Taiwan Earthquake Model (TEM) was established to assess the seismic hazard and risk for Taiwan by considering the social and economic impacts of various components from geology, seismology, and engineering. This paper gives the first version of TEM probabilistic seismic hazard analysis for Taiwan in these aspects. We named it TEM PSHA2015. The model adopts the source parameters of 38 seismogenic structures identified by TEM geologists. In addition to specific fault source-based categorization, seismic activities are categorized as shallow, subduction intraplate, and subduction interplate events. To evaluate the potential ground-shaking resulting from each seismic source, the corresponding ground-motion prediction equations for crustal and subduction earthquakes are adopted. The highest hazard probability is evaluated to be in Southwestern Taiwan and the Longitudinal Valley of Eastern Taiwan. Among the special municipalities in the highly populated Western Taiwan region, Taichung, Tainan, and New Taipei City are evaluated to have the highest hazard. Tainan has the highest seismic hazard for peak ground acceleration in the model based on TEM fault parameters. In terms of pseudo-spectral acceleration, Tainan has higher hazard over short spectral periods, whereas Taichung has higher hazard over long spectral periods. The analysis indicates the importance of earthquake-resistant designs for low-rise buildings in Tainan and high-rise buildings in Taichung. [ABSTRACT FROM AUTHOR]

Extant paper records of the early analog seismic network of Taiwan represent a large resource for earthquake studies in several disciplines. In this study, we report on T waves generated from offshore earthquakes, based on analog observations. The T phases were identified from their stable apparent velocity of about 1.5 km s-1 and other observations using data recorded by stations in eastern Taiwan and on two nearby islands. The observed T phases are recorded for the first time from Taiwan, and in particular are observed by the network in the distal range of local earthquakes. Most of the T waves are observed at island stations at epicentral distances greater than 100 km. For earthquakes that occurred a great distance east of Taiwan, the T phases are always the most dominant phases observed at island stations east of Taiwan, and are also seen at some inland stations with smaller amplitudes. No T phases from inland events were observed by stations on Taiwan or on nearby islands. The observations indicate that the amplitude of the T phase is highly attenuated on its land path and that the propagation direction of the T phase is affected by water depth. [ABSTRACT FROM AUTHOR]

Abstract: Wide-band magnetotelluric (MT) data were collected on an east–west profile, approximately perpendicular to the local strike of the Chelungpu thrust, through the hypocentral area of the Chi-Chi earthquake for imaging the seismogenic structure. MT data were then inverted for two-dimensional resistivity models plus best-fitting static shift parameters using a nonlinear conjugate gradient algorithm that minimizes the sum of the normalized data misfits and the smoothness of the model. As shown in the inverted 2D resistivity models presented in this paper, an electrical conductor beside the hypocenter of the Chi-Chi earthquake indicates that deep-crustal fluids may participate in the rupture process of the Chi-Chi earthquake. A striking spatial correlation between the crustal conductor and occurrence of aftershocks beneath the Chelungpu fault suggests a postseismic pore pressure adjustment ongoing after the mainshock. Additionally, the hypocenter exhibits an electrical resistive zone, consistent very well with a predicted compact zone from a crustal deformation and transient fluid flow modeling. [Copyright &y& Elsevier]

Abstract: The Jiufengershan rock avalanche was one of the largest and most damaging landslides triggered by the Chi-Chi earthquake (M L =7.3, M W =7.6) of 21 September 1999. The rock avalanche transported a mass of sedimentary rock 50 m thick and 1.5 km long, located on the western limb of the Taanshan syncline. The surface of rupture coincides with the bedding plane and dips moderately toward the Jiutsaihu valley. This paper is mainly devoted to the study of post-seismic surface processes that affected the sliding surface as well as the debris deposit, from September 1999 to February 2003. Large fractured blocks and a debris layer observed on the surface of rupture were subjected to mass wasting processes and denudation. The quantification of erosion was made using two different approaches. First, the subpixel correlation method was used to determine the horizontal displacement field from aerial photographs taken, respectively, 2 and 3.5 months after the earthquake. Displacements ranging from 1 to 6 m were observed around unstable blocks located at the western flank of the surface of rupture. Second, the co-seismic and post-seismic volume distributions in the sliding zone were determined from three digital elevation models, including a LiDAR image taken in 2002. Post-seismic erosion and deposition from September 1999 to April 2002 were mainly associated with mass wasting and denudation at the surface of rupture, deposition in small basins and lakes located in the debris deposit, and evacuation of materials from the debris deposit along natural and artificial drainage channels. The vertical compaction is 1% of the initial height of the deposit. [Copyright &y& Elsevier]

This paper focuses on the stress and strain rate field of the Taiwan area. The strain rate field in the Taiwan region is studied qualitatively and quantitatively, based on the GPS observation in 1990–1995. It reflects the accommodation of the ongoing lithospheric deformation within the seismogenic portion of lithosphere and exhibits zones with contrasting deformation modes and amounts. We then compare the obtained strain rate field with the tectonic information provided by studies of borehole breakouts and earthquake focal mechanisms for the Present, and by fault slip data analyses for the Quaternary period. In the first approximation, the stress and strain rate fields show spatial similarity. The orientation of principal shortening is generally consistent with the compressive stress orientation that reflects the oblique indentation of the Luzon Arc into the Eurasian continental margin. In more detail, significant anomalies in the deformation pattern deserve consideration in that they may reveal ongoing stress accumulation. Despite the short-term variations related to the earthquake cycle, some major features of the strain rate field, including the distribution of extension and compression, highlight the long-term tectonic behavior of the mountain belt at the lithospheric scale. The time and space variations of strain should be a function of local heterogeneity and be transferred between interseismic and coseismic periods. [Copyright &y& Elsevier]

In Central Taiwan, the destructive Chichi earthquake (Mw=7.6) of September 21st, 1999, produced a nearly 100-km-long rupture trace following the Chelungpu Fault. This paper shows how the geometry of the fault slip can locally be determined in three dimensions, based on analyses of earthquake fault in the Kuangfu stadium. The fault at this site is reverse and left-lateral. The three-dimensional geometrical analysis, done with a variety of data through independent determination modes, all applied to the deformation of the surface layer of the stadium tracks, allows complete verification of the results. Not only do these analyses constrain the fault behaviour in terms of trend, dip angle, obliquity and amount of slip, but also they reveal variations in both the horizontal and the vertical fault geometry. The comparison with relative displacements recorded at larger distances from the fault reveals that slip partitioning occurs, with nearly dip-slip thrusting along the rupture trace and distributed left-lateral shear in a deformed zone of the hanging wall, adjacent to the main fault. [Copyright &y& Elsevier]

Cities in seismic regions often have unknown numbers of older buildings vulnerable to strong earthquake ground motion. Simple methods are needed with urgency to screen these buildings. The problem is of immense proportions as it affects some of the largest cities in the world. Seismic vulnerability indices proposed by Hassan and Sozen (ACI Struct J 94(1):31-39, 1997), Islam et al. (Architectural Institute of Japan-Academic Lecture Collection Summary, 2017), NCREE (Chiou et al. in 16th World Conference on Earthquake Engineering, 16WCEE 2017, Santiago, 2017), and Shiga et al. (Proceedings, Tohuku District symposium, Architectural Institute of Japan, 1968) possess the required simplicity. The indices have different forms and have been calibrated through independent activities, but all imply that the key to building survival is in the relative sizes of elements resisting lateral inertial forces. Data collected after the 2016 Meinong, Taiwan, Earthquake were used to evaluate these indices. The evaluation showed that differences among indices did not lead to wide differences in the cost associated with a given benefit especially if they are used to include the effects of all lateral-load resisting elements including masonry infill. [ABSTRACT FROM AUTHOR]

Changes in groundwater level during earthquakes have been reported worldwide. In this study, field observations of co-seismic groundwater-level changes in wells under different aquifer conditions and sampling intervals due to near-field earthquake events in Taiwan are presented. Sustained changes, usually observed immediately after earthquakes, are found in the confined aquifer. Oscillatory changes due to the dynamic strain triggered by passing earthquake waves can only be recorded by a high-frequency data logger. While co-seismic changes recover rapidly in an unconfined aquifer, they can sustain for months or longer in a confined aquifer. Three monitoring wells with long-term groundwater-level data were examined to understand the association of co-seismic changes with local hydrogeological conditions. The finite element software ABAQUS is used to simulate the pore-pressure changes induced by the displacements due to fault rupture. The calculated co-seismic change in pore pressure is related to the compressibility of the formation. The recovery rate of the change is rapid in the unconfined aquifer due to the hydrostatic condition at the water table, but slow in the confined aquifer due to the less permeable confining layer. Fracturing of the confining layer during earthquakes may enhance the dissipation of pore pressure and induce the discharge of the confined aquifer. The study results indicated that aquifer characteristics play an important role in determining groundwater-level changes during and after earthquakes. [ABSTRACT FROM AUTHOR]

Tsunami disasters have been documented several times in Chinese history, mostly in the Taiwan region. To assess the tsunami hazard along the coast of mainland China from sources in Taiwan, this study analyzed historical tsunamis and undersea seismic events around Taiwan and found that the frequency and magnitude of earthquakes around Taiwan are significantly higher than in the adjacent Ryukyu and Manila trenches. The probabilistic seismic hazard analysis method was adopted to estimate the maximum possible earthquake magnitude around Taiwan. Then, six tsunami sources were assumed in those places where both earthquakes and tsunamis have occurred previously. Numerical models of the tsunamis were used to calculate the probable maximum tsunami amplitude and tsunami arrival time. The largest tsunami amplitude and the shortest arrival time were drawn on a GIS map. The modeling results provided a summary of tsunami hazards along the coast of mainland China from tsunami sources in Taiwan. The results showed that tsunamis triggered by the maximum possible earthquakes in the Taiwan region would arrive first at Zhejiang, Fujian, Guangdong, and Hainan Provinces within 3 h; the largest tsunami amplitude was up to 3.3 m. Thus, parts of Zhejiang, Fujian, and Guangdong Provinces were identified as regions with the highest hazard levels. [ABSTRACT FROM AUTHOR]

Taiwan is a young and seismically active mountain belt, where a series of strong earthquakes (M>7) have occurred over the past hundred years. Identifying historical earthquakes around Taiwan is a key to better constrain the geodynamic of this active region. Sedimentological and geochemical analyses of surface sediments from one station offshore east Taiwan revealed the presence of coarse-grained layers interpreted as turbidites. The age of these layers have been determined by 210Pb, 137Cs, and 241Am chronology. Dating of the three most recent turbidites provides ages of AD 2001±3, AD 1950±5, and AD 1928±10. The results show striking temporal correspondence of turbidite layers to large (M≥6.8) earthquakes recorded in the region since the 20th century. The chronologies of sediment layers lead us to believe that turbidites resulted from the 2003 Taitung earthquake (M 6.8), the 1951 Chengkong earthquake (M 7.1), and the 1935 Lutao earthquake (M 7.0), respectively. Such a good correlation between turbidites and high-magnitude (M≥6.8) historical and instrumental seismic events suggests that turbidite paleoseismology constitutes a valuable tool for earthquake assessment in the eastern Taiwan margin. Moreover, the modern reservoir radiocarbon age and the regional marine reservoir correction (ΔR) of the Kuroshio Current off Taiwan were estimated by comparing accelerator mass spectrometry (AMS) 14C ages with ages derived from corrected 210Pb profiles and historical accounts of identifiable seismic events. Such a determination is important to calibrate the 14C ages of marine materials for accurate comparison of marine and continental geological records. Our calculated mean ΔR value of 232±54 14C yr (n=2) is higher than its modern value of 86±40 14C yr. This high value can be explained by the presence of local upwelling cells and turbulence in the Kuroshio Current, north of Green Island. These upwelling cells bring 14C-depleted water to the surface, resulting in an increase of the modern ΔR value in this portion of the Kuroshio Current. [ABSTRACT FROM AUTHOR]

Advanced first-order second-moment (AFOSM) is commonly used to obtain an upper-bound estimate for a probabilistic analysis. This study presents a new AFOSM application to engineering seismology, estimating major earthquake probabilities based on fault length and slip rate, along with an earthquake empirical model subject to a model error of 0.26 M. The AFOSM analysis shows that the probability could be as high as 64 % for a major earthquake in northern Taiwan to exceed M 7.0, considering the length and slip rate of the Sanchiao fault are equal to 36 km and 2 ± 1 mm per year. By contrast, the other case study shows that for the Meishan fault in central Taiwan, the probability is 'only' 4 % for earthquake magnitude to exceed M 7.0, given a shorter fault length of 14 km and a larger slip rate of 6 ± 3 mm per year. [ABSTRACT FROM AUTHOR]

The region around Taiwan is known for active seismicity, and a few studies have reported a high seismic hazard in this region, including a deterministic seismic hazard analysis (DSHA) study. Essentially, DSHA is to estimate earthquake ground motions considering the worst-case earthquake size and location, but without considering the seismic hazards from non-controlling sources. Understandably, when many non-controlling sources are present, the original DSHA framework could be insufficient. Therefore, using the extreme probability theory, this study introduces a new DSHA framework taking non-controlling seismic sources into account during DSHA calculations. The new method was applied to a seismic hazard assessment for Taiwan, showing that near the conjunctions of seismic source zones, the increase in seismic hazard could be substantial after considering a total of 19 non-controlling sources. More importantly, like other seismic hazard assessments for Taiwan, this study conveys the same alarming message that a high level of seismic hazard should be present around the region. [ABSTRACT FROM AUTHOR]

This study explored how individuals in Taiwan perceive the risk of earthquake and the relationship of past earthquake experience and gender to risk perception. Participants ( n= 1,405), including earthquake survivors and those in the general population without prior direct earthquake exposure, were selected and interviewed through a computer-assisted telephone interviewing procedure using a random sampling and stratification method covering all 24 regions of Taiwan. A factor analysis of the interview data yielded a two-factor structure of risk perception in regard to earthquake. The first factor, 'personal impact,' encompassed perception of threat and fear related to earthquakes. The second factor, 'controllability,' encompassed a sense of efficacy of self-protection in regard to earthquakes. The findings indicated prior earthquake survivors and females reported higher scores on the personal impact factor than males and those with no prior direct earthquake experience, although there were no group differences on the controllability factor. The findings support that risk perception has multiple components, and suggest that past experience (survivor status) and gender (female) affect the perception of risk. Exploration of potential contributions of other demographic factors such as age, education, and marital status to personal impact, especially for females and survivors, is discussed. Future research on and intervention program with regard to risk perception are suggested accordingly. [ABSTRACT FROM AUTHOR]

Ergodicity is a behavior generally limited to equilibrium states and is here defined as the equivalence of ensemble and temporal averages. In recent years, effective ergodicity is identified in simulated earthquakes generated by numerical fault models and in real seismicity of natural fault networks by using the Thirumalai-Mountain metric. Although the effective ergodicity is already reported for Taiwanese seismicity, an immediate doubt is the unrealistic gridded sizes for discretizing the seismic data. In this study, we re-examined the effective ergodicity in Taiwanese seismicity by using reasonable gridded sizes which corresponded with the location errors in the real earthquake catalogue. Initial time and magnitude cut-off were examined for the validity of ergodic behavior. We found that several subsets extracted from Taiwanese seismicity possessed effectively ergodic intervals and all terminations of these ergodic intervals temporally coincided with the occurrences of large earthquakes ( M < 6.5). We thus confirm the ergodicity in the crustal seismicity by using the Thirumalai-Mountain metric. [ABSTRACT FROM AUTHOR]

We document and analyze incidents of liquefaction-induced lateral ground deformation at five sites located in the near-fault region of the 1999 Chi-Chi Taiwan earthquake. Each of the lateral spreads involved cyclic mobility of young alluvial soils towards a free face at creek channels. In each case, the lateral spreading produced relatively modest lateral displacements (approximately 10–200 cm) in parts of the spreads not immediately adjacent to channel slopes. For each site, we present displacement vectors across the spread features, which are based on mapping performed within three weeks of the earthquake. We review the results of detailed subsurface exploration conducted at each site, including cone penetration test soundings, borings with standard penetration testing, and laboratory index tests. We back-analyze the field displacements using recent empirical and semiempirical models and find that the models generally overestimate the observed ground displacements. Possible causes of the models’ overprediction bias include partial drainage of the liquefied soils during shaking, low but measurable plasticity of some of the soils’ fines fraction, and the absence of nonspread sites in the empirical databases used to develop existing empirical and semi-empirical lateral spread displacement prediction models. [ABSTRACT FROM AUTHOR]

Gas variations of many mud volcanoes and hot springs distributed along the tectonic sutures in southwestern Taiwan are considered to be sensitive to the earthquake activity. Therefore, a multi-parameter automatic gas station was built on the bank of one of the largest mud-pools at an active fault zone of southwestern Taiwan, for continuous monitoring of CO2, CH4, N2 and H2O, the major constituents of its bubbling gases. During the year round monitoring from October 2001 to October 2002, the gas composition, especially, CH4 and CO2, of the mud pool showed significant variations. Taking the CO2/CH4 ratio as the main indicator, anomalous variations can be recognized from a few days to a few weeks before earthquakes and correlated well with those with a local magnitude >4.0 and local intensities >2. It is concluded that the gas composition in the area is sensitive to the local crustal stress/strain and is worthy to conduct real-time monitoring for the seismo-geochemical precursors. [ABSTRACT FROM AUTHOR]

Statistical analysis using a discriminant model is applied to 399 cone penetration test (CPT) data sets of both liquefaction and nonliquefaction cases, including 174 sets from the Chi-Chi earthquake in Taiwan and 225 sets of synthesized data. The discriminant model employed is a multivariate statistical method. In situ testing results of cone tip resistance qc and sleeve friction ratio Rf are adopted as the major parameters for analyses. A model for evaluating liquefaction potential using CPT-qc data is also established in this study, which allows calculated results to be compared with the empirical curves. [ABSTRACT FROM AUTHOR]

We examine the post-seismic change in the groundwater level following the 1999 (Mw = 7.5) Chi-Chi earthquake in central Taiwan, as recorded by a network of 70 evenly distributed hydrological stations over a large alluvial fan near the epicenter. Four types of post-seismic responses may be distinguished. In type 1, the groundwater level declined exponentially with time following a coseismic rise. This was the most common response in the study area and occurred in unconsolidated sediments on the Choshui River fan. In type 2, the groundwater level rose exponentially with time following a coseismic fall. This occurred in the deformed and fractured sedimentary rocks in the foothills near the Chelungpu fault that ruptured in the Chi-Chi earthquake. In type 3, the groundwater level continued to decline with time following a coseismic fall. This also occurred in the deformed and fractured sedimentary rocks near the ruptured fault. Finally, in type 4, the groundwater level, following a coseismic rise, stayed at the same level or even rose with time before it eventually declined. This occurred mostly in unconsolidated sediments along the coast of central Taiwan and along the Peikang Stream. We analyze these post-seismic responses by using a one-dimensional model. Together with the results from well test, the analysis show that the type 1 response may be explained by an aquifer model with coseismic recharge and post-seismic subhorizontal discharge across a length of 500–5000 m; the type 2 response may be explained by a model of coseismic discharge and post-seismic recharge from surface water; the type 3 response may be explained by a model of coseismic discharge and post-seismic subhorizontal discharge across a length of 500–5000 m; and the type 4 response may be explained by a model of coseismic recharge and sustained post-seismic recharge from surface water. The characteristic time for the post-seismic changes is similar to that for the groundwater-level decline during dry seasons before the earthquake, suggesting that there was no earthquake-induced changes in the aquifer properties (i.e. hydraulic conductivity), confirming the earlier results from recession analyses of the post-seismic streamflow elsewhere after several earthquakes. [ABSTRACT FROM AUTHOR]

The sediment fluxes to the southwesternmost Okinawa Trough (SOT) off northeast Taiwan have been measured with four sets of sediment traps. The sediment fluxes observed were much higher than those in many marginal seas and showed great variations in time and space. The fluxes exhibited a drastic seaward decline from northeastern Taiwan to the central trough and an increase with depth. Temporal variability of fluxes was in a wide range from three times to one order of magnitude for certain traps. The observed sediment fluxes had a positive correlation with river runoff from the Lanyang Hsi, a river in northeastern Taiwan. Usually, the highest fluxes could be attributed to episodic events, for example, typhoon passages, which always cause ample rainfall leading to high runoff and sediment discharge, and sediment fluxes that were observed during typhoon passages accounted for more than 50% of the long-term flux. Large earthquakes are suggested to be responsible for some sediment flux anomalies observed on the nearby steep slope because of a good match in time between sediment collection and earthquake occurrence. A conceptual model is proposed to illustrate the sources and transport of the SOT sediment. The study highlights the greater contribution of Taiwan fluvial sediments to the SOT compared to that of the Changjiang, and it provides evidence demonstrating the combined effects of river runoff and large earthquakes on the sediment fluxes observed in such a deep marginal sea. [Copyright &y& Elsevier]

This study examines gestures, themes, message copy points and imagery, and strategy motives reflected in corporate advertising appearing in the China Times and United Daily News, two leading newspapers, in the month following the devastating Chin-Chin earthquake in Taiwan in September 1999. The study identified four possible corporate strategy motives in post-crisis corporate communications: social responsibility, communal relationship building, enlightened self-interest and impression management. A content analysis of adverts (n=100) suggested communal relationship building drove corporate advertising endeavours. Corporate philanthropy was the most common gesture described in the adverts, and the most frequent themes and message components focused on the restoration of society. No significant differences were found between companies headquartered in Taiwan versus elsewhere,or between companies headquartered in Asia versus the West. Implications for examining crisis communications and underlying motives behind public relations communications are discussed. [ABSTRACT FROM AUTHOR]