Ground-Motion Attenuation Relationships for Subduction-Zone Earthquakes in Northeastern Taiwan

Subduction zone earthquakes have not been taken into special consid- eration in most previous probabilistic seismic hazard analyses (PSHA) in Taiwan. However, they may be critical to properly analyze the earthquake hazard in metro- politan Taipei, so they need to be studied. Strong-motion data from subduction zone earthquakes, of both interface and intraslab types, obtained by the TSMIP and SMART1 arrays in northeastern Taiwan, are used to establish the attenuation equa- tions for peak ground acceleration (PGA) and response spectral acceleration (SA). The resultant PGA and SA attenuation equations include two site classes and two earth- quake source types. The ground-motion values predicted by these attenuation equa- tions are higher than those obtained from the crustal earthquake attenuation equations previously used in Taiwan but are lower than those predicted by the attenuation equa- tions for worldwide subduction zone earthquakes.