ON APPLICATION OF METHODS OF GLOBAL NAVIGATION SATELLITE SYSTEMS FOR TSUNAMI EARLY WARNING IN THE KURIL-KAMCHATKA REGION
Current Kuril-Kamchatka region’s tsunami warning system (TWS) is based on seismic methods that don’t allow to get accurate seismic source parameters in real-time that are needed for precise tsunami forecast. In addition, seismic methods utilization lead to magnitude underestimation in case of strong earthquakes (Mw > 8.0) which often occur in the Kuril-Kamchatka subduction zone. Over the last years, methods of Global Navigation Satellite Systems (GNSS-methods) are applied for solving of abovementioned issues in a number of foreign TWSs. The core of methodology is inversion of coseismic displacements detected by GNSS-stations into the earthquake source parameters and following calculation of sea bottom displacements and tsunami characteristics. Possibility of GNSS-methods application for regional TWS is considering in this work as an example of 1952 Kamchatka earthquake Mw8.7-9.0. Coseismic displacements at the locations’ of regional GNSS-stations modeled by Coulomb3.0 software and reference earthquake model were inverted according to different accuracy of offsets’ determination. Next, coseismic displacements of sea bottom were calculated using inverted fault planes and were compared with offsets corresponding to reference model. It was defined that adaptation of simple single plane fault’s model for inversion was possible to describe real source well. Initial sea bottom’s movements corresponding to inverted planes can to describe real offsets quite precisely. Accuracy of displacements’ determination of 3 cm in horizontal plane and 5 cm in vertical plane if enough for adequate estimation of earthquake’s parameters. Thereby, we confirmed that application of GNSS-methods and utilizing of existed regional GNSS-network is able to improve reliability of TWS significantly under current GNSS-techniques abilities.