The main purpose of the permanent GPS network of the Geophysical Institute, UNAM is to monitor the surface deformation on the Pacific coast of Mexico in order to study a cycle of large subduction thrust earthquakes.
Sismologia-UNAM GPS net-work is in continuous developing with a perspective to cover all south-ern Mexico coast where large de-structive subduction zone earth-quakes are a common natural phe-nomenon. At the present time the network consists of 19 continuously recording GPS stations.
The main cluster of GPS stations is installed in the NW of the Guerrero state where a large earthquake is expected in future. A study of crustal deformation during the interseismic period and before great earthquakes provides an advanced insight on the structure of the seismogenic zone and physical processes of earth-quakes generation.
Continuous GPS records revealed in 1998 and 2001 two slow slip tran-sients or silent earthquakes (SQ) in the subduction zone of Mexico. The silent earthquakes is an absolutely new type of elastic rebound events, which has been discovered recently in Japan, Alaska, Cascadia, New Zealand and Mexico. The SQs last from several days up to several years and it is believed that they may trigger large subduction earthquakes in mature seismic gaps like the Guer-rero seismic gap.
