A disastrous magnitude 6.1 earthquake hit Sinhua and Nabalin in the northeast of Tainan City on December 5, 1946 at 6:47 a.m. The seismic intensity of the earthquake reached 5 and in the epicenter region including Hsinhua, Hsinshih and Yongkang suffered the worst damage. Anding, Gueiren, Rende and Annan Townships and the Annan district in Tainan city suffered damage as well. Some significant ground deformation was found in the epicenter area, such as faults, fractures , sand boils, mud flow, water jetting, and water change in wells. These changes might have great impact on the local agriculture and transportation. According to an investigation, the Hsinhua fault was responsible for the quake. The shallow seismic profiles and field investigations indicated that the deformation zone is about several hundred meters long and consists of several normal faults that have been developed under an extensional tectonic environment. The Hsinhua Fault is an active fault of category one. The fault zone excavation inside the Livestock Research Institute showed that the rupture zone is in the Holocene Tainan Formation with a high-angel dip and shows to be a flower structure of transverse fault.

1. Huang, Sheng-Chien, et al. (2004). Shallow subsurface structures of Hsinhua Fault zone, Special Publication of the Central Geological Survey, 15, 99-110; 2. The causes of soil liquefaction, damage and rehabilitation, National Center for Research on Earthquake Engineering.