Fault frictional parameters and material properties revealed by slow slip events at Kilauea volcano, Hawai'i

Abstract

We categorize slow slip events at Kilauea Volcano into two distinct families based on GPS measurements of the surface displacement patterns. An event correlation filter confirms that "eastern" and "western" families are statistically distinguishable, with the western family notably self-similar. The western family exhibits quasi-periodicity with regular repeat times, while eastern family events are aperiodic or have complicated periodicity. If the decollement is the source fault for both families of events, it must have varying frictional properties at the ~10 km scale of separation. The temporal slip and spatial scaling behavior are consistent with a simplistic rate- and state-dependent frictional formalism provided that the characteristic slip distance for state evolution, D c, is of the order of millimeters rather than the 10-100 μm typically found in lab studies, and the shear rigidity is around 2 GPa, consistent with fault gouge material. Key Points Slow slip events at Kilauea can be categorized into two distinct families One family exhibits quasi-periodicity The periodicity constrains fault frictional parameters and material properties ©2013. American Geophysical Union. All Rights Reserved.