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Using multiple-scale mobile gravity data in the Sichuan-Yunnan area, we systematically analyzed the relationships between spatial-temporal gravity changes and the 2014 Ludian, Yunnan Province Ms6.5 earthquake and the 2014 Kangding Ms6.3, 2013 Lushan Ms7.0, and 2008 Wenchuan Ms8.0 earthquakes in Sichuan Province. Our main results are as follows. (1) Before the occurrence of large earthquakes, gravity anomalies occur in a large area around the epicenters. The directions of gravity change gradient belts usually agree roughly with the directions of the main fault zones of the study area. Such gravity changes might reflect the increase of crustal stress, as well as the significant active tectonic movements and surface deformations along fault zones, during the period of gestation of great earthquakes. (2) Continuous significant changes of the multiple-scale gravity fields, as well as greater gravity changes with larger time scales, can be regarded as medium-range precursors of large earthquakes. The subsequent large earthquakes always occur in the area where the gravity changes greatly. (3) The spatial-temporal gravity changes are very useful in determining the epicenter of coming large earthquakes. The large gravity networks are useful to determine the general areas of coming large earthquakes. However, the local gravity networks with high spatial-temporal resolution are suitable for determining the location of epicenters. Therefore, denser gravity observation networks are necessary for better forecasts of the epicenters of large earthquakes. (4) Using gravity changes from mobile observation data, we made medium-range forecasts of the Kangding, Ludian, Lushan, and Wenchuan earthquakes, with especially successful forecasts of the location of their epicenters. Based on the above discussions, we emphasize that medium-/long-term potential for large earthquakes might exist nowadays in some areas with significant gravity anomalies in the study region. Thus, the monitoring should be strengthened. [ABSTRACT FROM AUTHOR]

It is a common phenomenon that there exists shallow geotemperature rise precursor around an earthquake region before the event occurs. The existing models on geotemperature precursor mechanism such as the deep thermal ascent model and the model of hothouse effect, all encounter some contradictions although there is a certain evidence supporting them. From the angle of dissipative heat in the present paper, we set forth a new interpretation model named the stress-dissipative heat model with the main points of view as: the dissipative heat transformed from the work of crustal stress to non-elastic deformation of rock and soil, is one important reason for preseismic geotemperature rise. The medium-term regional and tendency geotemperature rise before an earthquake closely relates to the intensification of regional crustal stress field; the short-term and prequake geotemperature bursting rise around an earthquake region closely relates to rapid change of the source stress field. Plastic deformation and dissipative heat is much easier created in soil than rock. Therefore, the pre-earthquake geotemperature precursors mainly appear in soil covered area and mostly concentrate in shallow soil layers. [ABSTRACT FROM AUTHOR]

Based on Darcy-Gersevanov law concerning a flow relation between water and solids, we derive the horizontal movement of solid frame resulted from a discharging well in a Theis-Thiem confined system, and further analyze the relations among the horizontal movements and pumped time t as well as radius r from the discharging well. As applications of the theory, we propose some new interperations for ground fissure activity and casing failures induced by groundwater withdrawal or injection. [ABSTRACT FROM AUTHOR]