Data underlying the research of Abnormal Strain Induced by Heavy Rainfall on Borehole Strain meters Observed in Taiwan
datasetposted on 08.04.2020, 00:00 by Eric Chen
This study uses three network of borehole strainmeters located in Western Foothills of Taiwan orogenic belt resulted from the collision between the Philippine Sea plate and Eurasian plate to characterize the fast and slow responses of crustal strain during the heavy rainfall. This study mostly focuses on the fast rainfall-induced response of the observed areal strain in strainmeters. The fast and slow rainfall responses of areal strain data are separated using the technique of recursive digital filter. Moreover, the rainfall impact functions of the studied stations are calculated using deconvolution. The station located on flat ground shows that the rainfall impact function reaches the peak of 8.8 nanostrain/mbar after only a half hour of rainfall and then rapidly drops. The stations located in hilly regions suggest that the rainwater likely accumulates in low-lying zones and is difficult to disperse when the surrounding areas exhibit relatively large topographic surface changes. Whereas the river aside the station will help rising the velocity of runoff dispersion and reducing influence time in hill or mountain region. The effects of debris avalanches caused by intensive rainfall the mountain area can be viewed as two types of rock deformation generated only under the influence of rainfall and generated by the increased load in the river channels due to rainfall-induced landslides or debris flow. When the cumulative rainfall exceeds a certain threshold, the strain response curves likely show a noticeable anomaly due to the effects of the debris flow events in places prone to landslide.