Sayarim Infrasound Calibration Explosion: Near-Source and Local Observations and Yield Estimation.

摘要

A large-scale calibration explosion of about 82 tons of high explosives (HE), assembled as a pyramid on a soft sediment surface, was successfully conducted by the Geophysical Institute of Israel (GII) at Sayarim Military Range (SMR), Negev Desert, Israel, on 26 August 2009. Near-source high-pressure values, measured in the range 200600 m, were higher than predicted, whereas the resulting crater and the seismic magnitude were smaller than expected for this on-surface charge. These results confirm that the explosives, charge design, and upward detonation generated the necessary explosion energy and partition: a maximum of energy to the atmosphere and a minimum to the ground. The high-pressure observations were utilized for reliable estimation of the important ground truth parameter-TNT equivalent yield of about 0.1 kt, based on a stable integral characteristic of air-blast waves the positive phase impulse. As with near-source pressure gauges, anomalous enhanced peak pressure amplitudes were found at local infrasound stations, indicating possible an upward directivity effect and asymmetric energy radiation to the atmosphere. Clear infrasound signals were well observed at distances up to 3,500 km at numerous portable and permanent stations in Israel, Mediterranean countries, and north-central Europe, including two International Monitoring System (IMS) stations I26DE and I48TN, which provided for this region the first full GT0 source dataset for on-surface large-scale explosions recorded by infrasound stations of IMS. Additional estimations of the explosion yield, based on empirical scaling relations for the peak amplitude, dominant period, and crater dimensions, were analyzed. Yield estimations from far-regional IMS infrasound stations, obtained at the International Data Centre (IDC) using trial published empirical yield-range-amplitude attenuation laws, were significantly overestimated, thus indicating the need for refinement and tuning of the monitoring procedures.