Slow slip and tremor search at Kilauea Volcano, Hawaii

Abstract

AbstractKilauea Volcano, Hawaii, has hosted a long series of slow slip events observed since the installation of the continuous GPS network in 1996. Kilauea's slow slip events are inferred to occur on the decollement fault at 8 km depth beneath its south flank, with a location updip of the epicenters of large, regular earthquakes. Fault slip typically lasts about two days, and the events have magnitudes equivalent to Mw 5.3–6.0. While slow slip events in subduction zones are commonly accompanied by tectonic tremor (also called nonvolcanic tremor), no tremor has yet been reported in association with Kilauea's slow slip events. Instead, there are swarms of small triggered earthquakes, which is a characteristic only seen at select subduction zones (e.g., Boso and Hikurangi). A temporary array of seismometers was installed at Kilauea in 2007 in anticipation of a slow slip event. Here we use several established methods to perform a systematic search for tectonic tremor during geodetically defined slow slip events, as well as searching for tremor triggered by teleseismic surface waves. We do not detect tectonic tremor using any of these methods, although we are able to detect episodes of previously identified deep offshore volcanic tremor at 15–20 km depth and volcanic tremor from Kilauea. Although Kilauea's seismic network may not be adequate to observe tectonic tremor because Hawaii is seismically noisy and its crust is highly attenuating, it is also possible that the specific fault conditions on Kilauea's decollement are not conducive to such tremor generation.