‘Negative repeating doublets’ in an aftershock sequence

Implications of an inverse branching aftershock sequence model.

The branching aftershock sequence (BASS) model is a self-similar statistical model for earthquake aftershock sequences. A prescribed parent earthquake generates a first generation of daughter aftershocks. The magnitudes and times of occurrence of the daughters are obtained from statistical distributions. The first generation daughter aftershocks then become parent earthquakes that generate seco...

Static Stress Drop in the 1994 Northridge , California , Aftershock Sequence

We use time-domain pulse widths to estimate static stress drops for 279 M L 2.5 to 4.0 aftershocks of the 17 January 1994, M w 6.7 Northridge, California, earthquake. The stress drops obtained range from 0.02 to 40 bars, with a log average of 0.75 bar. Error bars computed for our estimates are typically a factor of 5, indicating that the three order of magnitude scatter in stress drops is not s...

Finding Approximate Repeating Patterns from Sequence Data

In this paper, an application of feature extraction from music data is first introduced to motivate our research of finding approximate repeating patterns from sequence data. An approximate repeating pattern is defined as a sequence of symbols which appears more than once under certain approximation types in a data sequence. By using the ‘cut’ and ‘pattern_join’ operators, we develop a level-wi...

Doublets in Translation

Aftershock Identification

Earthquake aftershock identification is closely related to the question “Are aftershocks different from the rest of earthquakes?” We give a positive answer to this question and introduce a general statistical procedure for clustering analysis of seismicity that can be used, in particular, for aftershock detection. The proposed approach expands the analysis of Baiesi and Paczuski [PRE, 69, 06610...