Changes of Groundwater Level due to the 1999 Chi-Chi Earthquake in the Choshui River Alluvial Fan in Taiwan
Resource
Bulletin of the Seismological Society of America 91 (5): 1062-1068
Journal
Bulletin of the Seismological Society of America
Journal Volume
91
Journal Issue
5
Pages
1062-1068
Date Issued
2001
Date
2001
Author(s)
Abstract
Changes of groundwater levels induced by the M L 7.3 Chi-Chi earthquake on 21 September 1999 were recorded at 157 out of 179 monitoring wells in the Choshui River alluvial fan.Of those, 67 observed large groundwater-level changes, ranging from 1.0 to 11.1 m.These 157 wells are clustered at 64 stations located approximately 2 to 50 km west of the north-south-trending Chelungpu fault.Both oscillatory and steplike changes of water level were observed on the analog records at the time of earthquake, while only steplike changes were observed on the hourly digital records.Coseismic changes of groundwater level were recorded not only in the confined aquifers but also in the partially confined aquifers and the unconfined aquifers.The recovery of water-level changes took minutes to months, depending primarily on hydrogeologic conditions of the confining layers.The sign and magnitude of coseismic water-level change at a well varied with its distance from the fault.The distribution of coseismic water-level changes induced by the Chi-Chi earthquake indicates that water-level rise predominated in most of the footwall area, whereas water-level fall prevailed in a narrow zone adjacent to the fault trace.
Type
journal article
File(s)![Thumbnail Image]()
Loading...
Name
02.pdf
Size
102.52 KB
Format
Adobe PDF
Checksum
(MD5):a58c94a558348c0191a4b60e91ba2d75