Abstract
Five year of data for microearthquakes originating in a small volume of crust near Socorro, New Mexico were analyzed to determine the temporal behavior of (1) the average number of shocks per unit time, (2) the slope of the earthquake-frequency graph, and (3) the energy release. Additional studies were made to establish the distribution function for the times observed between successive earthquakes and the hazard function.
The temporal behavior of the mean number of shocks per unit time and the slope of the earthquake-frequency law were found to be quite erratic until the observation period was increased to 2 or more years (more than 200 shocks detected). Large numbers of shocks generally produced large energy release but the converse was not always true. The distribution function for the observed interarrival times between events was found to differ significantly from exponential and normal distribution functions. This observation, along with the behavior of the hazard function, indicates that the microearthquake sequence studied did not follow a Poisson process.
