Analysis of Coseismic Effect of Digital Observation Water Level in Changli Well

This article sorts out the water level data of 19 strong distant earthquakes (M≥7.0) and two near-medium earthquakes (M≥4.0 within 300km) observed in Changli Well from March 29, 2005 to December 31, 2015. And statistics are also made from the aspects of spatial distribution and seismic parameters. At the same time, the characteristics and mechanism of co-seismic variation of water level are analyzed. The results show that: 1. Regardless of strong teleseismic or near-region moderate earthquakes, there are only two types of water level coseismic changes in this well: one is oscillation type; the other is pulse (or oscillation)-continuous rising type, and the second variation is often accompanied by the synchronous rise in water temperature in the same well; 2. The spatial location of strong teleseismic earthquakes generated pulses (or oscillations)—continuously rising coseismic changes is directional, and generally M ≥ 8.0, and the magnitude and epicentral distance have a good power function relationship with the magnitude of the order variation; 3. The elastic response of the aquifer to seismic waves is the main reason for the oscillation type change; Changli Well has a good geological structure environment. When a strong earthquake occurs at the same time, the stress (energy density) of the well-aquifer system increases significantly, and the permeability of the aquifer increases accordingly. The tidal factor and phase difference of the M₂ wave changed abnormally before and after the earthquake, which may be the reason for the rise of the water level change; At the same time, according to the position of the water temperature probe in the same well is in a positive gradient change layer, the water level rises and the water temperature also rises, which is the main reason for the simultaneous rise of the water level and the water temperature.