5:15 PM - 6:30 PM
[SCG60-P06] Water flux model around TRIES/MIU to explain the gravity change - II
Keywords:Gravity, Ground Water, Coseismic Response
In this report, we first reviewed the effect of ground deformation including the afterslip to the gravity data obtained in and around the TRIES/MIU. Ground water level is almost recovering in this 5 years, nevertheless the gravity values are still same as of just after the earthquake. Coseismic vertical displacement is less than 1 cm in the study area, which gravitational effect is about 1 micro Gal. Postseismic vertical displacement shows about 4 cm uplift in the last 5 years. This is an amount of 9 micro Gal decrease for the gravity, which cancels the coseismic step. We conclude that the gravitational effect of the ground water level recovery is masked by the effect of postseismic displacement. We also studied the individual coseismic ground water level response for all the wells in the study area, including reported in Niwa et al. (2012). For each well, we compiled the amount of change, time to the peak of the change, duration for the recovery and so on. The correlation was found between the recovery speed and the water catchment area on the basement topography. We also quested for the implication of downward water flow in the wells where the water pressure is monitored by multi packer system.