Broadband Downhole Seismic Array at National San-Chung Commercial and Industrial Vocational High School,

New Taipei City

operated by IES in September, 2009

In 2004, the Institute of Earth Sciences (IES) of Academia Sinica was contracted by the Central Geological Survey (CGS) of the Ministry of Economic Affairs to initiate a four year project ofuGeophysical investigation and monitoring for micro-earthquake in metropolitan Taipeiv. The purpose of this project is to investigate, evaluate and continuously monitor the seismic activities of the faults and low frequency tremors in the Taipei Metropolitan Area (TMA). The IES was given the responsibility for setting up a portable broadband seismic network covering the TMA in 2004 and continued in the process of more site selections to install stations from 2005 to 2009. Because the Taipei Basin is a densely urbanized area with wide diffusion of roads and railway traffic, industries and agricultural activities the high cultural noise produced by these activities represents a serious problem which affects seismic observations. Therefore, four permanent broadband downhole seismic arrays were also established to avoid noise on the alluvium plain in this project. Installation of these four stations was completed in 2005 at Daan Park (DANB), 2006 at Guandu Nature Park (GDUB), 2007 at Sinjhuang Life Hall Park (SNJB) and 2008 at  Panchiao Pader Park (PADB).

The initial phase of the downhole seismic observations in TMA was finished in June 2007. In order to continue providing basic ground motion data to evaluate site response effects in this area, the CGS decided to initiate the second phase of the program in the TMA to continue monitoring earthquakes. Selection of the boreholes is dependent on the site conditions (geology, communications, and accessibility) and the position of the present downhole network. The new borehole in 2009 is at National San-chung Commercial and Industrial Vocational High School..