A semi-automatic detection system of non-volcanic tremor in Taiwan

• Main Authors: Yu-ling Chuang, 莊育菱
• Other Authors: Kate Huihsuan Chen
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/31882049680004089139

碩士 === 國立臺灣師範大學 === 地球科學系 === 100 === In a transition zone between stable sliding and locked faults, occurrence of noise-like, non-volcanic tremors (NVT) are found to play an important role in full spectrum of strain release processes. The triggered and ambient tremor episodes previously discovered in Taiwan illustrates the generation potential of non-volcanic tremors underneath Central Range. However, small tremor bursts (several to tens of minutes) with high noise level and spare seismic station coverage makes the automatic detection in this region problematic and challenging. We propose an automatic detection scheme to identify tremors in this particular region. Applying this detection method in the two years data starting from January, 2009, we found 121 ambient tremor episodes with duration ranging from 5 to 30 minutes. The detected tremor events are confined in a small area of 23 x 55.5 km2 with the depth range of 16-34 km. We also obs erve larger number of tremors at the time of two local M6 earthquakes. Such acceleration lasted 70 and 90 days after the mainshocks. Given the uncertainty of assumed tremor source model, the static stress triggering relationship between M6 event and tremor is inconclusive. The scaling relationship between the duration and amplitude of ambient tremors fits an exponential model, suggesting a scale-bound source process.