Co-seismic Earthquake Lights: The Underlying Mechanism
- 146 Downloads
Earthquake lights (EQLs) have long been considered mysterious natural phenomena, for which no good physical explanation seemed to be available. Crucial to understanding EQLs, in particular the intense flashes of light bursting out of the ground while S waves propagate, is the presence of peroxy defects in igneous rocks, in particular in gabbroic rocks that typically fill the subvertical dykes in regions of past extensional tectonics. The peroxy defects tend to locate along grain boundaries or may even link adjacent mineral grains, making them highly susceptible to ever so slight displacements of mineral grains. Thus, the passage of an S wave will instantly activate peroxy bonds. If the number density of the stress-activated peroxy is so high that their delocalized wave functions overlap, the entire rock volume must instantly expand, supported from within by an electronic degeneration pressure. This process will be followed by a momentary dissociation of the peroxy defects, generating e′ and h· charge carriers, causing the volume to instantly contract again, at least partly. If an electric discharge can burst out from the top of the dyke, removing some of the charge carriers and generating an EQL, an additional volume contraction can be expected occur.
KeywordsEarthquake lights earthquake lightning earthquake flashes triboluminescence piezoelectric piezomagnetic active faults electric breakdown arcing flashover transformer explosions
I thank an anonymous reviewer tor very insightful comments and suggestions. This study draws on work that was supported by the NASA Ames Research Center through several “Director’s Discretionary Fund” (DDF) grants, by the NASA “Earth Surface and Interior” (ESI) Grant 2010 NNX08AG81G_S03, and through a Goddard Earth Science and Technology (GEST) Fellowship at the Geodynamics Branch, NASA Goddard Space Flight Center. I thank Dr. Bobby SW Lau and Dr. Akihiro Takeuchi for their contributions to the experimental work. I thank Professor Charles W. Schwartz, Department of Civil and Environmental Engineering, University of Maryland, for laboratory support.
- Anonymous. (2010). Registran enormes luces en el cielo durante terremoto de 8.8 grados de magnitud que destruyó Chile, in Actualidad, Lima, Peru. https://web.archive.org/web/20100301224159/http://www.peru.com/noticias/portada20100228/83581/Registran-enormes-luces-en-el-cielo-durante-terremoto-de-88-grados-de-magnitud-que-destruyo-Chile.
- Bortnik, J., Bleier, T. E., Dunson, G., & Freund F. (2010). Estimating the seismotelluric current required for observable electromagnetic ground signals. Annales Geophysicae 28, 1625–1624. https://doi.org/10.5194/angeo-28-1615-2010.
- Chen, Q.-F., & Wang, K. (2010). The 2008 Wenchuan earthquake and earthquake prediction in China. Bulletin of the Seismological Society of America, 100(58), 2840–2857. https://doi.org/10.1785/0120090314.
- Corliss, W. R. (1982). Lightning, Auroras, Nocturnal Lights: A Catalog of Geophysical Anomalies. The Sourcebook Project, Glen Arm, MD. 248 pages, 74 illustrations, 1070 refs. ISBN 915554-09-7.Google Scholar
- Derr, J. S. (1973). Earthquake lights: a review of observations and present theories. Bulletin of the Seismological Society of America, 63, 2177–2187.Google Scholar
- Diaz, A., Friedman, J. S., Luciano, S., Martinez, S., Hernandez, A., de Jesus, J., & Maldonado, P. M. (2015). Propagation of Electromagnetic Waves through Homogeneous Media, paper DTE06 presented at ETOP Meeting of the Optical Society of America.Google Scholar
- Fidani, C. (2010b). ELF signals by Central Italy electromagnetic network in 2008–2010, paper presented at GNGTS-Gruppo Nazionale di Geofisica della Terra Solida. Italy: Trieste.Google Scholar
- Freund, F., Batllo, F., & Freund M. M. (1990). Dissociation and recombination of positive holes in minerals. In L. M. Coyne, S. W. S. McKeever & D. F. Blake (Eds.), Spectroscopic characterization of minerals and their surfaces (pp. 310–329). American Chemical Society, 390 https://doi.org/10.1021/bk-1990-0415.ch016.
- Freund, M. M., Freund, F., Butow, S., Korvink, J. G., & Baltes, H. (1996). Hole injection into MgO from self-trapped positive hole pairs, paper presented at American Physical Society. APS, St. Louis, MO, USA: Annual March Meeting.Google Scholar
- Freund, F. T., Hoenig, S. A., Braun, A., Momayez, M., & Chu, J. J. (2010). Softening rocks with stress activated electric current, paper presented at 5th International Symposium on In-situ Rock Stress (ISRSV). China: Beijing.Google Scholar
- Freund, F. T., Takeuchi, A., & Lau, B. W. (2006). Electric currents streaming out of stressed igneous rocks—A step towards understanding pre-earthquake low frequency EM emissions. Physics and Chemistry of the Earth, 31, 396–399.Google Scholar
- Freund, F., Whang, E.-J., Batllo, F., Desgranges, L., Desgranges, C., & Freund, M. M. (1994). Positive hole– type charge carriers in oxide materials. In L. M. Levinson & S.-I. Hirano (Eds.), Grain boundaries and interfacial phenomena in electronic ceramics (pp. 263–278). Amer. Ceram. Soc.: Cincinnati, OH.Google Scholar
- Galli, I. (1910). Raccolta e classificazione dei fenomeni luminosi osservati nei terremoti. Bolletino della Societa Sismological Italiana, 14, 221–448.Google Scholar
- Lamica, C. (2014). Earthquake lights Santa Rosa/Napa earthquake, https://www.youtube.com/watch?v=RknvjVTCFhM.
- Matsushiro-Earthquake-Center. (2000). Catalogue of literature and documents on the Matsushiro Earthquake Swarm. https://dil-opac.bosai.go.jp/publication/nied_tech_note/pdf/KJ-01_198.pdf.
- McMillan, W. G. (1985). Earthquake light. In Final Report, 1 Mar. 1983–15 Aug. 1986 McMillian Science Associates, Inc., Los Angeles, CA. Rep. AD-A61385 (p. 53). Geophysics/STI, Los Angeles.Google Scholar
- Papadopoulos, G. (1999). Luminous and fiery phenomena associated with earthquakes in the East Mediterranean. In M. Hayakawa (Ed.), Atmospheric and ionospheric electromagnetic phenomena associated with earthquakes (pp. 559–575). Tokyo: Terra Scientific Publishing.Google Scholar
- USGS. (2018). Earthquake Booms, Seneca Guns, and Other Sounds. https://earthquake.usgs.gov/learn/topics/booms.php.
- West, M. (2017). Explained: Mexico City Earthquake Lights [Power Line Arcing and Transformer Explosions], Metabunk.org; https://www.metabunk.org/explained-mexico-city-earthquake-lights-power-line-arcing-and-transformer-explosions.t9044/.
- Yasui, Y. (1973). A summary of studies on luminous phenomena accompanied with earthquakes. Memoirs Kakioka Magnetic Observatory, 15(2), 127–138.Google Scholar