Abstract
Abstract. Past studies that attempted to quantify the spatio-temporal organization of seismicity have defined the conditions by which an event and those that follow it can be related in space and/or time. In this work, we use the simplest measures of spatio-temporal separation: the interevent distances R and interevent times T between pairs of successive events. We observe that after a characteristic value R*, the distributions of R begin to follow that of a randomly shuffled sequence, suggesting that events separated by R > R* are more likely to be uncorrelated events generated independent of one another. Interestingly, the conditional T distributions for short-distance (long-distance) events, R ≤ R* (R > R*), peak at correspondingly short (long) T values, signifying the spatio-temporal clustering (separation) of correlated (independent) events. By considering different threshold magnitudes within a range that ensures substantial catalogue completeness, invariant quantities related to the spatial and temporal spacing of correlated events and the rate of generation of independent events emerge naturally.
Highlights
A better understanding of the processes governing seismicity, coupled with the advancements in instrumentation, resulted in the ability to measure and record the time of arrival, hypocentre location, and magnitude of an earthquake event with a substantially high level of sensitivity
Decades-long catalogues of earthquake events for different regions and even for a global scale are available for study
They report observable differences between the return time distributions of regional and global earthquake catalogues: the histogram of interevent times of southern California earthquakes shows two distinct peaks, signifying the difference in characteristic waiting times between correlated and independent events, while global statistics reveals a single characteristic peak due to overlapping sequences from various locations. They explain the results using the epidemic-type aftershock sequence (ETAS) model (Kagan and Knopoff, 1981; Ogata, 1988; Sornette and Helmstetter, 2002), a five-parameter model wherein the main-shock generation rate μ is used as a proxy for spatial extent
Summary
A better understanding of the processes governing seismicity, coupled with the advancements in instrumentation, resulted in the ability to measure and record the time of arrival, hypocentre location, and magnitude of an earthquake event with a substantially high level of sensitivity. They report observable differences between the return time distributions of regional and global earthquake catalogues: the histogram of interevent times of southern California earthquakes shows two distinct peaks, signifying the difference in characteristic waiting times between correlated (same aftershock sequence) and independent (different sequences) events, while global statistics reveals a single characteristic peak due to overlapping sequences from various locations They explain the results using the epidemic-type aftershock sequence (ETAS) model (Kagan and Knopoff, 1981; Ogata, 1988; Sornette and Helmstetter, 2002), a five-parameter model wherein the main-shock generation rate μ is used as a proxy for spatial extent. Our analyses are guided by the fact that spatio-temporal clustering is a well-established phenomenon in seismicity (Utsu and Ogata, 1995; Kagan and Knopoff, 1980) and must manifest even in the simplest measures of spatiotemporal separations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
