[F16] Analysis of magnitude distribution in large earthquake sequences in Japan
| Affiliation | ETH Zurich |
|---|---|
| Presenter | Mirwald Aron |
Keywords
- B-value
- Time-series
- Japan
Outline
The b-value of the Gutenberg–Richter law describes the relative frequency of earthquake magnitudes, and is often observed to vary over time and space. Such variations have been reported to be caused by several factors, including tectonic stress, depth, and fore‐ and aftershock activity. The b‐value is highly relevant in the context of earthquake forecasting because it directly translates into probabilities of future large earthquakes, making it a key component in state‐of‐the‐art earthquake hazard and forecasting models.
The nature of reported b-value variations is still controversial in the scientific community. While some already use b-value variations for practical applications, others find that changes in b-values do not represent a reliable indicator of physical quantities or future seismicity. In order to contribute to the ongoing scientific debate and clarify the nature of b-value variations, we recently developed a method to quantify the significance of the b-value variation (Mirwald et al., 2024), called b-significant.
In this work, we systematically investigate the b-value variation of large earthquake sequences in Japan by applying the b-significant method. First, we test if the b-value in large earthquake sequences vary more than expected due to random chance. Second, we explore if there are any consistently occurring spatial patterns of b-values before or after large earthquakes.
