Answer:
Due to fluid flowing down to the fracture
Step-by-step explanation:
Many scientist and policy maker discovered that depth-volume joint impacts are critical, and the amount of INJECTED MATERIAL becomes more important at point where surface of sedimentary rocks contact crystalline strata rocks and it is capable to cause earthquakes — The main reason behind this massive earthquake is the percolation through deep well which allow easy access to liquid to flow down to fracture that are more susceptible to earthquake.