1. Coseismic water level oscillation and correlated deep water temperature changes have been observed in a water well at Tangshan City by high sensitivity measurement.

2. The amplitude of coseismic groundwater level wave is related to magnitude and epicentral distance of the earthquake.

3. Earthquake liquefaction, caused by coseismic shakes, is controlled by soil conditions which are the results of geomorphic processes.

4. Following the idea of coseismic stress-triggering, coseismic strain steps recorded by borehole strainmeters are used to study coseismic stress-triggered fault slips.

5. A comparison was made between first stage of the recordings and the late ones on coseismic step jump information and precursory abnormal phenomena.

6. Based on these theoretical simulation and analyses, we study the coseismic and postseismic deformation of strong earthquake in detailed.

7. Strain steps recorded by borehole strainmeters are of special values in studies of coseismic stress triggered fault activities.

8. Because of the different geographical position, geological structure, depth and aquifer rock, coseismic groundwater level changes of the same earthquake in the two wells are different.

9. The gravity changes in the southwestern China may be produced by the coseismic gravity changes of the Lijiang earthquake.