Infrasound Calibration Experiment at Sayarim, Israel: preliminary tests

We are establishing a Ground Truth (GT0) infrasound dataset for Middle East/Mediterranean region, through conducting a series of surface explosions at Sayarim Military Range (SMR), Negev desert, which culminated with an 82-ton explosion in August 2009. The dataset will be used to characterize the infrasonic propagation in the region, depending on source features and atmosphere conditions, and thus to improve monitoring capabilities of International Monitoring System (IMS). Test explosions of broad yield range and various designs were conducted on the first stage, in different days and seasons, thus providing a wide range of atmospheric conditions. The goals were to: 1) test charge design and assembling, and train procedures of logistics and coordination, for preparation and conducting of the main explosion; 2) analyze atmospheric effects on infrasound propagation in different azimuths based on collected meteo-data. In June-July 2008, we conducted a series of 13 detonations of outdated ammunition (in the range 0.2-10 ton) and two experimental shots of 1 ton of different explosives (TNT and Composition B). The two shots were placed close to an ammunition explosion and 10 min afterwards to help estimate ammunition actual yield (TNT). Some of these explosions were observed at IMS station I48TN (Tunisia) at ~2500 km, using array processing and analysis. Two test explosions of 1 ton and 5 tons of different recuperated HE explosives were conducted at SMR in December 2008. High-pressures in air-shock waves at close distances (150-250 m) were measured and speed video recording was done. The data obtained from the test series provided estimation of the explosion yield, that showed approximate TNT equivalency. We analyzed signals from the tests, recorded on seismic and acoustic channels at near-source and local distances. We compared energy generation for different explosives, including cratering conditions, and investigated the influence of wind direction on infrasound arrivals. Modeling of long range atmospheric propagation of infrasound was conducted using global G2S atmospheric profiles and collected local atmospheric data. The optimal date and time window of the experiment as well as the locations of portable infrasound systems in Mediterranean region were selected based on experimental and infrasound modeling results.