A Joint Satellite and Ground-Based Study of Temporal-Spatial Evolution
Patterns of Pre-Earthquake Signals Associated With Major Earthquakes
Abstract
We present an interdisciplinary study of observations of pre-earthquake
processes associated with major earthquakes based on integrating space
and ground- data. Recent large magnitude earthquakes in Asia and Europe
have emphasized the various observations of multiple types of
pre-earthquake signals recorded either on the ground or from space. Four
physical parameters were measured from ground and satellite and used in
our simulation models: 1) Ground Radon variation; 2) Outgoing
Long-Wavelength Radiation (OLR) obtained from NPOES, NASA/AQUA) on top
of the atmosphere (TOA); 3) Atmospheric Chemical Potential (ACP)
obtained from NASA assimilation models and; 4) electron density
variations in the ionosphere via GPS Total Electron Content (GPS/TEC).
For this analysis we selected six large earthquakes from the last decade
with differing geographic and seismo-tectonics regions: (1) M9.3, Off
the West Coast of Northern Sumatra, Dec 26, 2004; (2) M9.0 Great Tohoku
Earthquake, Japan, March 11, 2011; (3) and (4) M7.8 and M7.3 Gorkha,
Nepal, 2015; (5); M8.2 Tehuantepec, Mexico, September 8, 2017 and; (6)
M7.1, Puebla central Mexico earthquakes, September 19, 2017. Our
preliminary results indicate an enhancements of radon (about a week to
ten days prior) coincident (with some delay) with an increase in the
atmospheric chemical potential measured near the epicenter from both
satellite and subsequently with an increase of outgoing infrared
radiation (OLR) observed on the TOA from NOAA/NASA (a week in advance).
Finally GPS/TEC data indicate an increase of electron concentration 1-4
days before the earthquakes. Although the radon variations and some of
satellite OLR anomalies were observed far (>2000km) from
the epicenter areas the anomalies were always inside the estimates of
the Dobrovolsky-Bowman area of preparation. We examined the possible
correlation between magnitude and the spatial size of earthquake
preparation zone in the framework of the Lithosphere –Atmosphere
-Ionosphere Coupling hypothesis. The reliable detection of
pre-earthquake signals for both sea and land earthquakes was possible
only by integrating satellite and ground observations. A detail summary
of our approach to this study of pre-earthquake research has just been
published as AGU/Wiley Geophysical Monograph Series No. 234.