Last night, a 7.0 magnitude shallow earthquake struck Bacheng County, Nangqu City, Tibet, causing significant casualties. Experts from China Earthquake Networks Center (CENC) analyzed the quake as a typical shallow earthquake with a shallow hypocenter of only 10 kilometers, located within the Qiangtang block, and only 2 kilometers from the closest fault. The earthquake, triggered by the collision and compression of tectonic plates, is a 'tensile rupture.' Experts predict a risk of further 5.0 or higher magnitude aftershocks in the next few days, cautioning rescue teams and local residents to be vigilant.

BACKGROUND

The quake occurred in the central Tibetan Plateau, specifically within the Qiangtang block. Since 1900, the Qiangtang block has experienced only six earthquakes of magnitude 7.0 or higher. Due to the minimal damping of earthquake waves in the ground, and the high destructive power of the transverse waves, coupled with the fragmented rocks in the area, secondary disasters such as landslides and rockfalls are likely. Already, over 500 aftershocks have been recorded.

EXTENDED INTERPRETATION

The crustal deformation in the Tibetan Plateau is primarily caused by the strong collision and compression between the Indian and Eurasian plates, leading to the uplift of the Tibetan Plateau. Simultaneously, material extends in the east and west, forming a strong 'tensile' environment. According to the seismic mechanism analysis, the 7.0 magnitude earthquake was a strike-slip 'tensile rupture,' which perfectly matches the local geologic structures. However, compared to the common reverse faulting and compression in tectonic plate boundaries, tensile structures are generally less likely to accumulate the strength to generate major earthquakes. Thus, the magnitude 7.0 is quite unusual in this context.