Analysis of Volcanic Earthquakes of Asamayama (Japan)

Abstract

The statistical theory of point processes has been used to analyze a series of observations on volcanic earthquakes derived from the Japanese volcano Asamayama. Preliminary studies of the observations disclose a seeming cyclicity. The earthquakes do not occur in accordance with a Poisson type of process, nor are the intervals between events independently distributed, but there is a tendency for the events to cluster (high coefficient of variation). An analysis of the serial correlation coefficients leads to the rejection of a renewal hypothesis, and specific tests for renewal hypotheses support this conclusion. Analysis of the periodogram shows the existence of significant trend in the data, and specific tests lead to the rejection of the hypothesis of independence between intervals. The analysis of the graph of the logarithmic empirical survivor function shows it to differ from the form expected for exponentially distributed times between events.