Deterministic Seismic Hazard Analysis in Thailand using Active Fault Data

Abstract

To develop seismic design criteria for buildings, seismic hazard analysis is required to estimate the ground motion intensity with criteria such as peak ground acceleration (PGA). The seismic hazard can be analyzed by using two approaches: deterministic seismic hazard analysis (DSHA) and probabilistic seismic hazard analysis (PSHA). In these two approaches, the seismic hazard is evaluated from past earthquake events and active faults data. In Thailand, seismic hazard is classified in the low lying regions; however, in recently years, earthquakes have occurred frequently in the North of Thailand. To prevent and reduce damage due to earthquakes in the future, determination of seismic hazard is needed. This research proposes a deterministic seismic hazard map evaluated from nineteen active faults affecting Thailand. Two types of active faults are considered: first, an active fault in a subduction zone and second, a crustal fault. The seismic hazard is evaluated by using a ground motion prediction equation (GMPEs). Four GMPEs are weighted equally for seismic crustal fault, and two GMPEs are weighted equally for a seismic subduction zone. The hypocentral distance is used to evaluate the seismic hazard for all ground motion prediction equations. The Northern part and the Western part of Thailand are high seismic hazard regions, because there are active faults with the large possibility of earthquakes of a maximum magnitude. The seismic hazards in the North, West and Northeast of Thailand are about 0.60 g. The seismic hazard in Bangkok is about 0.25 g due to the Three Pagoda fault and Sri Sawat fault. The seismic hazard in the South of Thailand is about 0.40 g.

Keywords

• Active faults
• Deterministic seismic hazard assessment
• Seismic hazard map of Thailand