Awidely cited theory associates active faults with earthquakes in china and southeast asia. this theory suggests

east asia is moving toward the himalaya, causing faulting and earthquakes
india is moving west relative to eurasia, pulling central asia away from east asia
subduction beneath east asia is pushing east asia toward the himalaya, forming young mountains between the himalaya and pacific subduction zones
india is plowing into the "soft underbelly" of asia, pushing east asia eastward

The correct answer is - India is plowing into the ''soft underbelly'' of Asia, pushing East Asia eastward.

Since India hit into the Eurasian plate its movement has never stopped since then. India is sunbducting bellow Eurasia, but with the subduction it has caused significant lifting up of the surrounding area, with the highest mountain range in the world, the Himalayas, being the most marking product of that. As India still continues to push inside Eurasia and continues with the subduction, more and more cracks appear in the crust. These cracks cause the formation of faults. Because of the pressure that enables the formation of the faults, lot of crust is cracking deep into the ground, and as it cracks and breaks, lot of gaps are opening up. The rocks than adjust, and as they do they release a lot of energy. That energy release results in the formation of numerous earthquakes in the surrounding areas like the western half of China and the northwestern and northern part of Southeast Asia.