Origin of Earthquake Light Associated with Earthquakes in Christchurch, New Zealand, 2010-2011

Abstract

Earthquake light (EQL) mainly blue-white flashes from the ground, was observed coseismically during a New Zealand M7.1 earthquake, (4.47 am 4-Sep-2010 local time). A local production mechanism is most probable. The blue-white flash observations support the Freund et al. mechanism, i.e. shockwave disturbance creating electronic "holes" from ruptured peroxy bonds in quartz, and subsequent surface positive charge from the ground, followed by light emission during neutralization. Examination of video records shows the flash median length is about half a second and needs to be differentiated from the light during electricity supply short circuits. Observed ground-level white colors appear to result from very intense non-specific air ionization. Blue colors seem to be nitrogen emission with a short lifetime, succeeded by green oxygen emissions with longer lifetime followed by much lower intensity red. These were created by transient low-to-moderate voltages and probably include significant UV production. The maximum likely radiation dose is small, restricted to the skin, and equivalent at most to a few months natural background radiation. Calculations confirm the release of 222 Rn is not the major mechanism for creating earthquake light, and would contribute minimal radiation dose. Other unique observations are: streamers of light changing from blue to green as they passed from west to east, vertical sheets of blue-green light from cracks in an asphalt road surface, created by local shockwaves and shearing forces, daylight observation by fishermen of rapid linear undersea travel of blue light seconds before a 2011 M6.0 aftershock, and a mid-day green-blue glow over nearby hills containing a fault zone, shortly before the further destructive M6.3 earthquake, (12.51 pm 22-Feb-2011).Las luces de terremoto o EQL (del inglés "Earth Quake Light") son principalmente azul blancas y fueron cosísmicamente observadas durante un terremoto de magnitud 7.1 en Nueva Zelanda (4:47 a.m., 4 de septiembre de 2010, hora local). Es muy probable que el fenómeno haya sido producto de un mecanismo local. Las observaciones del destello azul blanco coinciden con el mecanismo de Freund y otros, esto es, la alteración de un movimiento sísmico que crea "agujeros" electrónicos a partir de lazos de ácido peroxi rotos en cuarzos, con carga positiva superficial consecuente del suelo, y seguida por la emisión de luz durante la neutralización. La revisión de grabaciones de video muestra que la duración del destello es de cerca de medio segundo y debe ser diferenciado de la luz generada por los cortos circuitos del fluido eléctrico. Los colores blancos observados a nivel del terreno parecen resultar de una intensa ionización aérea no específica. Los colores azules serían emisiones de nitrógeno con un corto período de duración, sucedidas por emisiones de oxígeno verde de mayor duración y seguidas por un rojo mucho menos intenso. Estos colores fueron creados por voltajes transitorios de bajo a moderados y probablemente incluyen una producción significativ...

Blue sky at midnight – earthquake lightning

“…The mean and standard deviation were 0.59 ± 0.27 s. The median was 0.57 s, the maximum was 1.36 s, and the minimum was 0.04 s (one frame long). These correspond well with previously found values in New Zealand (Whitehead and Ulusoy, 2015) and the derived rule of thumb for the median length remains half a second. The Kobe data medians of Yasui (1968) and Tsukuda (1997) are longer, but the many flashes with times below 1 s are excluded in their compilation because video analysis was not generally available.…”

“…The strongest colors in the Taita clouds in Figure 14, viewed from below, seemed to be white only, with no blue halo, but the surroundings at ground level showed a blue tinge. Some of the white color is due to sensor saturation, but also as discussed previously (Whitehead and Ulusoy, 2015) the white colors are a mixture of all colors and should be attributed to nonspecific air ionization caused by sufficient voltages, rather than an unlikely carefully balanced combination of primary colors.…”

A Critical Review of Ground Based Observations of Earthquake Precursors

“…Photographic and video evidences are certainly a valuable tool to support the reliability and objectivity of claimed observations, but published testimonies leave room for uncertainty and interpretation. Despite the large amount of testimony collected in published about EQLs (see also Lockner et al, 1983;Johnston, 1991;Whitehead and Ulusoy, 2015 and reference therein), it appears that the rate of observation by witnesses for EQLs is significantly lower than even the most conservative estimates of hallucination prevalence in the normative population. This consideration is neither a bias due to the authors' skepticism nor a preclusion against the investigation and existence of EQLs, but something that should be cautiously taken into account when assessing the reliability of this intriguing phenomenon.…”

Earthquake and Electrochemistry: Unraveling the Unpredictable

“…Radon gas anomalies in groundwater and soil gas was studied aiming to predict earthquake (5). Earthquake light (EQL) was observed just before or during strong earthquake events (40). Electrical field-induced ionization of different crustal elements could easily dissolve in groundwaters, leading to a change of groundwater chemistry.…”