Satellite observation of CH 4 and CO anomalies associated with the Wenchuan M S 8.0 and Lushan M S 7.0 earthquakes in China

Abstract

Spatial and temporal variations of total column of CH 4 and CO (TotCH 4 and TotCO) associated with the 12 May 2008 Wenchuan and 20 April 2013 Lushan earthquakes in western Sichuan, China were investigated using satellite data from AQUA AIRS in order to understand the lithospheric and atmospheric interactions during the seismic activity. The Wenchuan M S 8.0 and Lushan M S 7.0 earthquakes occurred in the Longmenshan fault zone. It was observed that large amounts of gases emitted from the earth's crust into the atmosphere before, during and after the earthquakes. The anomalies of TotCH 4 and TotCO occurred along the fault zone, and the peak values were found at the intersection areas where the crust stress approached the maximum. Furthermore, temporal anomalies of TotCH 4 and TotCO occurred during and after the Wenchuan earthquake, but 3 months before the Lushan earthquake. The anomalies related to the Lushan earthquake could be partially attributed to the Wenchuan earthquake because of the seismotectonic changes and fractures in the crust produced by the Wenchuan earthquake.

Analysis of spatiotemporal variations in middle-tropospheric to upper-tropospheric methane during the Wenchuan <i>M</i><sub>s</sub> = 8.0 earthquake by three indices

“…The total column of CH 4 associated with the 12 May 2008 Wenchuan earthquake was investigated using satellite data from the AQUA Atmospheric Infrared Sounder (AIRS), and this work indicates that a large amount of CH 4 was emitted from underground into the atmosphere along the Longmenshan fault zone, from approximately 1.5 months before to 3 months after the earthquake, and the closer to the epicenter, the larger the amount of emitted gas. The peak values were found at intersection areas (Yue, 2013;Cui et al, 2017). However, the same column concentration might correspond to this distinct vertical structure.…”

Land – Atmosphere – Meteorological coupling associated with the 2015 Gorkha (M 7.8) and Dolakha (M 7.3) Nepal earthquakes

“…In some earthquakes, anomalous CO prior to earthquakes have been observed (Singh et al, 2010a;Cui et al, 2017;Jing et al, 2018).We have used CO data retrieveed from the Measurements of Pollution in the Troposphere (MOPITT) instrument onboard the NASA Earth Observing System (EOS) Terra satellite platform to study emissions of CO from the active fault zones associated with earthquake activities. The MOPITT satellite provides data on the vertical distribution of CO in the troposphere that detects atmospheric CO absorption at a solar band around 2.3 mm and a thermal band around 4.6 mm (Deeter et al, 2004).…”

“…Since last three decades, analysis of geophysical, geological, hydrological, satellite and model data have shown changes in subsurface, land, meteorological and atmospheric parameters prior and after the earthquakes (Gornyi et al, 1988;Tronin, 1996;Dey and Singh, 2003;Ouzounov and Freund, 2004;Saraf and Choudhury, 2005;Tramutoli et al, 2005;Maeda and Takano, 2010;Singh et al, 2010a;Wu et al, 2012;Daneshvar et al, 2014;Ye et al, 2015;Cui et al, 2017;He et al, 2017;Jing et al, 2018;Qin et al, 2018). These abnormal signals occurred in lithosphere and atmosphere during the earthquake preparation process, and usually appear several months or several days prior to the earthquake event.…”

Tectonic Controls on Near-Surface Variations in CH4 and CO2 Concentrations along the Northwestern Margin of the Ordos Block, China

“…Tectonic stress affects gas emission in complex ways, although a good correlation exists between the soil gas concentration and stress in the crust [23,24]. Degassing can be enhanced by a large number of fractures formed under the action of stress, while pathways of gas emission can shrink or even become blocked when stress is concentrated, thereby inhibiting emission, for example, little gas emissions from the Longmenshan fault zone before the Wenchuan Ms 8.0 earthquake of May 12, 2008, which was caused by the locked fault hardly without deformation under the long-term strain accumulation [27,38,39]. Correlations between fault stress and geochemical and fluid-related earthquake precursors were studied by Martinelli & Dadomo [25], and their results suggested that greater seismic precursory phenomena occur at faults under lower stresses.…”

“…The results of field investigations [20,[22][23][24], statistical phenomena [25], and dynamic experiments on rocks [26] have also demonstrated that the stress associated with crustal deformation affects earth degassing. In addition, atmospheric CH 4 and CO 2 anomalies related to fault zones and the accumulation of tectonic stress have been observed in satellite hyperspectral data [27].…”