Non-volcanic tremors associated with slow slip event in South Central Alaska between 2010-2013. Submitted to Earth and Planetary Science Letters. Abstract

abstract

  • Abstract: A slow slip event between 2009 and 2013 has been recorded in south central Alaska near the epicenter of the 1964 M9.2 earthquake. It is unclear if there is any change of non-volcanic tremors associated with the slip event. We search for tremor signals from January 2010 to May 2015 using seismic data from a local seismic network in this region. The data are filtered using a band-pass filter between 1-6 Hz. Potential tremors are detected using a waveform envelope method and are then visually inspected under several general criteria for validation. The observed tremors were recorded in a time series portraying frequency of occurrence per month. There was a decreasing trend in tremor activity from 2010 to 2013 that leveled off in 2014. This shows that tremor activity did intensify during the slip event and returned to normal after the conclusion of the slow slip event. Seasonal variations in tremor activity with a peak in summer are also observed and are likely related to the seasonal hydrological loading. We locate five tremors using a 1D seismic velocity model, and their horizontal locations are near the downdip limit of the slow slip area. The depth of tremors is not well resolved due to the limited number of seismic stations in this region. Our study confirms the occurrence of non-volcanic tremors associated with the 2009-2013 slow slip event in south central Alaska.

authors

publication date

  • 2016

presented at event