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Research
Infrasound publications
Evidence of a meteoritic origin of the September 15th, 2007 Carancas crater
A. Le Pichon, K. Antier, Y. Cansi, B. Hernandez, E. Minaya, B. Burgoa, D. Drob, L.G. Evers and J. Vaubaillon Abstract On September 15th, 2007, around 11:45 local time in Peru, near the Bolivia's border, the atmospheric entry of a meteoroid produced bright lights in the sky and intense detonations. Soon after, a crater was discovered South of the Lake Titicaca. These events have been detected by the Bolivian seismic network and two infrasound arrays operating for the Comprehensive Nuclear-Test-Ban Treaty Organization, situated at about 80 and 1620 km from the crater. The localization and origin time computed with the seismic records are consistent with the reported impact. The entry elevation and azimuthal angles of the trajectory are estimated from the observed signal time sequences and back-azimuths. From the crater diameter and the air-wave amplitudes, the kinetic energy, mass and explosive energy are calculated. Using the estimated velocity of the meteoroid and similarity criteria between orbital elements, an association with possible parent asteroids is attempted. The favorable setting of this event provides a unique opportunity to evaluate physical and kinematic parameters of the first actual seismic recording of a terrestrial meteorite impact.
Propagation of infrasonic waves in the direction of I41PY for different source heights (A, B, C, D: 10, 25, 35 and 50 km, respectively) and a frequency of 1 Hz. The NRL-RAMPE parabolic equation method (Lingevitch et al., 2002) combined with the environmental profiles derived from the G2S atmospheric model are compared to a 3D ray traces adapted from the Tau-P method (Garces et al., 1998). Since effects of the boundary conditions of the propagation domain are particularly important in the high-altitude Andes region, simulations account for the NOAA Global Land One-km Base Elevation (GLOBE) digital terrain elevation model (Hastings and Dunbar, 1998). According to these simulations, the recorded signals at I41PY can be explained by multiple stratospheric returns.
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