Neotectonic architecture of Taiwan and its implications for future large earthquakes

Abstract

[1] The disastrous effects of the 1999 Chi-Chi earthquake in Taiwan demonstrated an urgent need for better knowledge of the island's potential earthquake sources. Toward this end, we have prepared a neotectonic map of Taiwan. The map and related cross sections are based upon structural and geomorphic expression of active faults and folds both in the field and on shaded relief maps prepared from a 40-m resolution digital elevation model, augmented by geodetic and seismologic data. The active tandem suturing and tandem disengagement of a volcanic arc and a continental sliver to and from the Eurasian continental margin have created two neotectonic belts in Taiwan. In the southern part of the orogen both belts are in the final stage of consuming oceanic crust. Collision and suturing occur in the middle part of both belts, and postcollisional collapse and extension dominate the island's northern and northeastern flanks. Both belts consist of several distinct neotectonic domains. Seven domains (Kaoping, Chiayi, Taichung, Miaoli, Hsinchu, Ilan, and Taipei) constitute the western belt, and four domains (Lutao-Lanyu, Taitung, Hualien, and Ryukyu) make up the eastern belt. Each domain is defined by a distinct suite of active structures. For example, the Chelungpu fault (source of the 1999 earthquake) and its western neighbor, the Changhua fault, are the principal components of the Taichung Domain, whereas both its neighboring domains, the Chiayi and Miaoli Domains, are dominated by major blind faults. In most of the domains the size of the principal active fault is large enough to produce future earthquakes with magnitudes in the mid-7 values.

Centroid Fault-Plane Inversion in Three-Dimensional Velocity Structure Using Strong-Motion Records

“…Chen et al (2008) suggested that there are two faults delineated by seismicity distribution with backthrust and strike-slip faulting mechanisms. The right-lateral Meishan strike-slip fault, located at the northern margin of our study region, acts as a tearing fault (Shyu et al, 2005). According to our results for the focal mechanisms and hypocentral depths shown in Figure 8, the west-dipping trend of the fault is consistent with a dominant backthrust.…”

Hydrochemical Changes in Spring Waters in Taiwan: Implications for Evaluating Sites for Earthquake Precursory Monitoring

“…Presently, rapid crustal movement and widely distributed active structures are the geological characteristics of this young tectonic entity (Yu et al 1997(Yu et al , 1999Chang et al 1998). Hence, in terms of tectonic activity, seven and four neotectonic domains, respectively, can be identified in western and eastern Taiwan, and what's more, each domain is bound by its own distinct active structure (Shyu et al 2005). Beyond this, each may have its own response to stress accumulation and faulting.…”

Campaigned GPS on Present-Day Crustal Deformation in Northernmost Longitudinal Valley Preliminary Results, Hualien Taiwan

“…5). The western margin of the HUAL block is defined following the eastern margin of the Central Range, which corresponds to a geologically suspected fault, the Central Range Fault (Biq 1965;Lu and Hsu 1992;Shyu et al 2005). A recent study on local seismicity (Chen et al 2012) suggested a seismically active structure along the edge of the Central Range in the Hualian City area.…”