Taiwan (TEM)

Authors:

Y.-J. Wang, C.-H. Chan, Y.-T. Lee, K.-F. Ma, J.-H. Shyu, R.-J. Rau, C.-T. Cheng

Summary

Coverage of Taiwan is with the 2015 hazard model developed within the Taiwan Earthquake Model (TEM) initiative (Wang et al., 2016). The model was originally implemented for the OpenQuake (OQ) engine.

Information about the OQ model versions and input files can be found on the Results and Dissemination page.

Interactive Viewer

The viewer below depicts the seismic sources and hazard results in terms of PGA for a return period of 475 years. Click on the menu in the upper right corner to select the layer.

viewer_legend

Tectonic overview

The island of Taiwan occupies a position along the convergent margin between the Philippine Sea Plate and the marginal plates of eastern Asia. The west-dipping Ryukyu Trench extends to the north to Japan, while the east-dipping Manila Trench runs south of the island to the Philippines. These systems come together in a bivergent thrust belt that cuts through the island, producing major reverse earthquakes on faults such as the Chelungpu Thrust.

Basic Datasets

Please refer to Wang et al. (2016).

Hazard Model

Seismic Source Characterisation

The Taiwan hazard model includes the following seismic sources, modelled as the listed OpenQuake source typologies:

  • Background seismicity in active shallow crust, modelled as 28 area sources with truncated Gutenberg-Richter MFDs.
  • 38 crustal faults are modelled as simple fault sources with characteristic occurrence rates confined to a single magnitude bin.
  • The Manila and Ryukyu-arc subduction interfaces were modelled as simple faults with characteristic occurrence rates. The Manila interface was divided into three segments.
  • Intraslab earthquakes for both subduction zones are modeled as simple faults according to the subducting slab depth contours with truncated Gutenberg-Richter MFDs.

All sources were used together in a single logic tree branch. The sources can be visualized in the interactive viewer, and are described in detail in Want et al. (2016).

Ground Motion Characterisation

Active Shallow Crust Weight
Lin2009 1.0
Subduction Interface Weight
LinLee2008SInter 1.0
Subduction Inslab Weight
LinLee2008SSlab 1.0

Hazard Calculations

Hazard curves were computed with the OQ engine for peak ground acceleration (PGA) and spectral acceleration (SA) at 0.2s, 0.5s, 1.0s, and 2s. The computation was performed on a grid of 2027 sites (spaced at approximately 10 km) with reference soil conditions with shear wave velocity in the upper 30 meters (Vs30) of 760-800 m/s.

The hazard map for PGA corresponding to a 10% probability of exceedance in 50 years (475 year return period), can be seen using the interactive viewer. For a more comprehensive set of hazard and risk results, please see the GEM Visualization Tools.

References

Wang, Yu-Ju, Chung-Han Chan, Ya-Ting Lee, Kuo-Fong Ma, J. Bruce H. Shyu, Ruey-Juin Rau, and Chin-Tung Cheng. "Probabilistic seismic hazard assessments for Taiwan." Terr. Atmos. Ocean. Sci. 27, no. 3 (2016): 325-340.