Articles | Volume 4, issue 5/6
Nat. Hazards Earth Syst. Sci., 4, 793–798, 2004

Special issue: Precursory phenomena, seismic hazard evaluation and seismo-tectonic...

Nat. Hazards Earth Syst. Sci., 4, 793–798, 2004

  30 Nov 2004

30 Nov 2004

Interpretation of the microwave non-thermal radiation of the Moon during impact events

V. Grimalsky1, A. Berezhnoy3,2, A. Kotsarenko4, N. Makarets5, S. Koshevaya6, and R. Pérez Enríquez4 V. Grimalsky et al.
  • 1Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Puebla, Mexico
  • 2Advanced Research Institute for Science and Engineering, Waseda University, Tokyo, Japan
  • 3Now at: Sternberg Astronomical Institute, Moscow University, Moscow, Russia
  • 4Centro de Geociencias, Juriquilla, UNAM, Querétaro, Mexico
  • 5Kyiv National Shevchenko University, Faculty of Physics, Kyiv, Ukraine
  • 6Universidad Autonoma del Estado de Morelos (UAEM), CIICAp, Cuernavaca, Mexico

Abstract. The results of recent observations of the non-thermal electromagnetic (EM) emission at wavelengths of 2.5cm, 13cm, and 21cm are summarized. After strong impacts of meteorites or spacecrafts (Lunar Prospector) with the Moon's surface, the radio emissions in various frequency ranges were recorded. The most distinctive phenomenon is the appearance of quasi-periodic oscillations with amplitudes of 3–10K during several hours. The mechanism concerning the EM emission from a propagating crack within a piezoactive dielectric medium is considered. The impact may cause the global acoustic oscillations of the Moon. These oscillations lead to the crackening of the Moon's surface. The propagation of a crack within a piezoactive medium is accompanied by the excitation of an alternative current source. It is revealed that the source of the EM emission is the effective transient magnetization that appears in the case of a moving crack in piezoelectrics. The moving crack creates additional non-stationary local mechanical stresses around the apex of the crack, which generate the non-stationary electromagnetic field. For the cracks with a length of 0.1–1µm, the maximum of the EM emission may be in the 1–10GHz range.