Development of the new seismic network of the IGS, Armenia

Abstract

The Republic of Armenia and the neighboring areas are located in the central part of theArabia-Eurasia collision zone, which is characterized by active seismicity.Over the past decade, the Institute of Geological Sciences (IGS) of NAS RA has developed an advanced and dense seismic network.To develop the local seismic network, the Institute of Geological Sciences in collaboration with the National Taiwan University and Institute of Earth Sciences, Academia Sinica (Taiwan) established 11 seismic stations with broadband seismometers and 6 cGPS (continuous) stations. Data from the existing seismic stations were collected, archived and treated, and main earthquake parameters were determined; the conducted works included catalogue maintenance, recalculation of the main earthquake data, calculation of seismic tomography with the input of recalculated and updated data, and adjustment of the three-dimensional (3D) velocity model for the area of the RA. Starting from 2017, the Institute of Geological Sciences has participated in two partner ISTC projects: A-2334 Project (Transect) “The Uplift and Seismic Structure of the Greater Caucasus” and KR-2452 Project (SNECCA) “Seismic Network Expansion in the Caucasus and Central Asia” with support from the U.S. Department of Energy.  In the framework of the indicated projects, 32 seismic stations with broadband seismometers were established along with 8 seismic borehole stations with fully broadband seismometers (Real Time) and 8 strong motion sensors. These two projects are implemented through the Seismic Targeted Initiative of the International Science and Technology Center and the Science and Technology Center in Ukraine.The records collected from the eight (8) already operational permanent seismic stations of the indicated network are in real-time mode sent to the International Seismology Center of the IRIS (Incorporated Research Institutions for Seismology). To download and archive the database of seismic stations, a new computer server was acquired under the project, and all required configurations were made to provide for its uninterrupted operation. Seiscomp software set is applied to produce automatic solutions for earthquakes recorded within the region. Adjustments and recalculations of the automatic earthquake solutions are implemented to produce the resulting main earthquake parameters with uncertainties reduced to the rate as low as possible. The collected data from all existing stations are widely used to determine and to re-estimate the main parameters of earthquake occurring in Armenia and in surrounding territories. These data are included in local bulletins and catalogues.For strong motions, the on-going research includes processing of design accelerograms, preparation and analysis of hazard response spectra (RS), selection of the actually recorded (real) acceleration time-history, and spectral matching of the time-history to the hazard response spectrum with application of Seismosoft (Earthquake Engineering Software Solutions, SeismoMatch, SeismoSignal, SeismoSelect, SeismoSpec) software set.All the results obtained from the data seismic stations mentioned above are used for the purposes of scientific research and are summarized in articles.