TY - JOUR ID - epos165 UR - http://dx.doi.org/10.5194/npg-17-293-2010 IS - 4 A1 - Cho, N. F. A1 - Tiampo, Kristy F. A1 - Mckinnon, S. D. A1 - Vallejos, J. A. A1 - Klein, W. A1 - Dominguez, R. Y1 - 2010/07/02/ N2 - The Thirulamai-Mountain (TM) metric was ?rst developed to study ergodicity in ?uids and glasses (Thiru- malai and Mountain, 1993) using the concept of effective ergodicity, where a large but ?nite time interval is consid- ered. Tiampo et al. (2007) employed the TM metric to earth- quake systems to search for effective ergodic periods, which are considered to be metastable equilibrium states that are disrupted by large events. The physical meaning of the TM metric for seismicity is addressed here in terms of the cluster- ing of earthquakes in both time and space for different sets of data. It is shown that the TM metric is highly dependent not only on spatial/temporal seismicity clustering, but on the past seismic activity of the region and the time intervals consid- ered as well, and that saturation occurs over time, resulting in a lower sensitivity to local clustering. These results con?rm that the TM metric can be used to quantify seismicity clus- tering from both spatial and temporal perspectives, in which the disruption of effective ergodic periods are caused by the agglomeration of events. PB - American Geophysical Union JF - Nonlinear Processes in Geophysics VL - 17 SN - 1607-7946 TI - A simple metric to quantify seismicity clustering SP - 293 AV - none EP - 302 ER -