Assessing active faulting by hydrogeological modeling and superconducting gravimetry: A case study for Hsinchu Fault, Taiwan

Tzuyi Lien, Ching Chung Cheng, Chein-way Hwang*, David Crossley

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

We develop a new hydrology and gravimetry-based method to assess whether or not a local fault may be active. We take advantage of an existing superconducting gravimeter (SG) station and a comprehensive groundwater network in Hsinchu to apply the method to the Hsinchu Fault (HF) across the Hsinchu Science Park, whose industrial output accounts for 10% of Taiwan's gross domestic product. The HF is suspected to pose seismic hazards to the park, but its existence and structure are not clear. The a priori geometry of the HF is translated into boundary conditions imposed in the hydrodynamic model. By varying the fault's location, depth, and including a secondary wrench fault, we construct five hydrodynamic models to estimate groundwater variations, which are evaluated by comparing groundwater levels and SG observations. The results reveal that the HF contains a low hydraulic conductivity core and significantly impacts groundwater flows in the aquifers. Imposing the fault boundary conditions leads to about 63-77% reduction in the differences between modeled and observed values (both water level and gravity). The test with fault depth shows that the HF's most recent slip occurred in the beginning of Holocene, supplying a necessary (but not sufficient) condition that the HF is currently active. A portable SG can act as a virtual borehole well for model assessment at critical locations of a suspected active fault. Key Points Hydrodynamic model and gravity are integrated to assess if a fault is activeHsinchu Fault in a high-tech area of Taiwan may be active from our resultSG works as a virtual borehole well at critical locations for fault assessment

Original languageEnglish
Pages (from-to)7319-7335
Number of pages17
JournalJournal of Geophysical Research: Solid Earth
Volume119
Issue number9
DOIs
StatePublished - 1 Sep 2014

Keywords

  • Hsinchu Fault
  • MODFLOW
  • active faulting
  • groundwater
  • superconducting gravity

Fingerprint Dive into the research topics of 'Assessing active faulting by hydrogeological modeling and superconducting gravimetry: A case study for Hsinchu Fault, Taiwan'. Together they form a unique fingerprint.

Cite this