Satellite observation of CH4 and CO anomalies associated with the Wenchuan MS 8.0 and Lushan MS 7.0 earthquakes in China

Spatial and temporal variations of total column of CH4 and CO (TotCH4 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 MS 8.0 and Lushan MS 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 TotCH4 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 TotCH4 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.