THE FIRST VERY-SMALL-APERTURE SEISMIC ARRAY IN IRAN FOR MONITORING EARTHQUAKES AND VOLCANIC ACTIVITIES IN DAMAVAND REGION; A PRELUDE TO AN EARLY WARNING SYSTEMFOR METROPOLITAN TEHRAN

To monitor possible seismic activities related to Damavand Volcano and earthquakes associated with Mosha Fault Zone, a very small aperture seismic array was deployed to the foot of the Damavand Volcano. The array proved to be capable of detecting small events which otherwise were not reported by permanent networks due to their sparsedistribution of stations in the region. There were also tremor like phenomena observed which might be related to Damavand volcano, a dormant volcano which constantly emits fumarolic gases and hosts a number of hot springs on its flank. The array boosted by installation of a high accuracy GPS station for future seismogeodetic measurement may be seen as a prelude for an early warning system for metropolitan Tehran. Seismic arrays since the start of their deployment in 1950’s (have undergone continuous improvement both in configuration and instrumentation to meet various needs from monitoring nuclear explosions to detection of earthquakes and microtremors. Array seismology has therefore played a major role for monitoring local regional and teleseismic events. What differentiates a modern seismic array from traditional networks is not its configuration or equipment but rather the methods used in analysis of their data. In order to test the capability of a very small aperture seismic array which is easier to deploy than other alternatives, a site close to Damavand volcano which is in fact the abandoned construction camp of Lar water dam, around 70 km northeast of Tehran was chosen (Figure 1).