Tremor-tide correlations at Parkfield, CA
Abstract
Recent studies linking non-volcanic tremor activity with tidal forcing have focused on short-term episodic tremor in subduction zone environments. In this study, we analyze the effect of tidal stresses and stress rates on tremor occurrence and magnitude at Parkfield, CA to determine if the Parkfield tremor, as a more continuous phenomena and in a different tectonic regime, demonstrates the same relationship to tides as its transient counterpart. For each of the 1777 tremor events in the 6-year catalog, we compute the volumetric, normal, shear, and coulomb stresses and stress rates for the central tremor zone at the initiation time of each event. Assuming that tremor and tides are uncorrelated, the percentage of tremor that occurs under a specific loading condition should be directly proportional to the percentage of time (normalized over the duration of the catalog) spent under those loading conditions. Using this as our null hypothesis, we assess the statistical significance of the deviations from this hypothesis to determine which conditions have the most profound influence on NVT.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.U33A0053N
- Keywords:
-
- 7218 Lithosphere (1236);
- 7223 Earthquake interaction;
- forecasting;
- and prediction (1217;
- 1242)