Waveforms cross-correlation from Natron-Manyara (Oldoinyo Lengai) array to find repeating earthquakes

Abstract

In the field of seismology, waveform cross correlation has been known to be a powerful method to find repeating earthquakes and to get insights into their source mechanisms based on the waveform similarities. Oldoinyo Lengai, the only known carbonatite volcano in the world is in the East African Rift, which exhibits complex tectonic and magmatic processes within a geologically active setting. We perform waveform cross-correlation analysis to identify repeating earthquakes to distinguish between faulting, magmatic, and hydrothermal systems in this region. Using seismic data from a network of stations, we apply a correlation coefficient of 0.9 to detect high similarities between waveforms. Our results reveal only a few repeating earthquakes, suggesting that extensional strains accommodated by multiple faults with varying orientations rather than being localized to border fault zones. The presence of non-similar waveforms highlights the complexity of seismic processes, including pressurized magma bodies and hydrothermal activity. While continuous monitoring is essential for mitigating seismic hazards, our findings underscore the need for long-term studies to better characterize the processes leading to repeating earthquakes. Although earthquake prediction remains challenging, long-term monitoring can provide valuable insights into the underlying mechanisms and improve our ability to assess and mitigate seismic risks. Contrary to the statement that events located in the same family have same source mechanisms, we observed different source mechanisms within earthquake families, indicating a heterogeneous tectonic environment with irregular strains. Therefore, combining waveform analysis with other techniques such as focal mechanism plotting can help resolve ambiguities in distinguishing source mechanisms. Overall, this research contributes to a better understanding of seismic activity in the East African Rift and its implications for seismic hazard assessment and mitigation strategies