Slow Rupture Velocity Research Articles

Slow initial phase of the P‐wave velocity pulse generated by microearthquakes

It was found that the initial rise of the far‐field P‐wave velocity pulse generated by microearthquakes does not act as a ramp but gradually increases according to the function tn (2<n<4), where t is the time measured from the onset. This slow rise of the P‐wave velocity pulse was termed the slow initial phase. The slow initial phase can not be explained by theoretical source models which assume a constant kinematic friction and a constant rupture velocity but by models which predict slow slip velocities and/or rupture velocities immediately after the rupture is initiated, such as the slip‐weakening crack model.