May 12th 2008: a 7.8 earthquake occurred in Wenchuan, Sichuan province, west China.
This is more evidence of the strong correlation between the mantle, fault lines, seismic activity, earthquakes, and hydrocarbons.
Sichuan is China's largest natural gas basin.
See Eugene Coste's Rock Disturbances Theory of Petroleum Emanations
Thomas Gold of course mentions this in Chapter 8 of the Deep Hot Biosphere: Rethinking Earthquakes.
Gold suggests that movement of primordial hydrocarbons also may be responsible for earthquakes that occur away from fault lines, and that release of methane and other light hydrocarbons is a prelude to an earthquake.Also see Zhonghao Shou Earthquake Clouds And Short Term Prediction.
(3) Gas emission: Sulphureous gas emitted before the Haicheng earthquake , and so did carbon- dioxide before the Tangshan earthquake [9, 10].
(4) Earth-flash: At 19:36 of February 4, 1975, one minute or more before the quake, the No. 31 express train of Dalian-Beijing was approaching the Tang-Wang-Shan station near Haicheng. "Very bright purplish red flashes suddenly glittered in the dark sky before the train.