| Title | Synchronized and asynchronous modulation of seismicity by hydrological loading: a case study in Taiwan |
| |
| Author | Hsu, Y; Kao, H ;
Burgmann, R; Lee, Y; Huang, H; Wu, Y; Zhuang, J |
| Source | Science Advances vol. 7, no. 16, eabf7282, 2021 p. 1-12, https://doi.org/10.1126/sciadv.abf7282  Open Access |
| Image |  |
| Year | 2021 |
| Alt Series | Natural Resources Canada, Contribution Series 20200734 |
| Publisher | AAAS |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf; html |
| Area | Taiwan, Province of China |
| Lat/Long WENS | 119.6667 122.2500 25.3333 21.8333 |
| Subjects | tectonics; geophysics; hydrogeology; Science and Technology; Nature and Environment; Health and Safety; seismology; seismicity; earthquakes; earthquake risk; seismic risk; groundwater levels; satellite
geodesy; navigation satellites; fluid dynamics; pore pressures; global navigation satellite systems (GNSS) |
| Illustrations | location maps; charts; seismograms |
| Program | Environmental Geoscience Shale Gas - induced seismicity |
| Released | 2021 04 14 |
| Abstract | Delineation of physical factors that contribute to earthquake triggering is a challenging issue in seismology. We analyze hydrological modulation of seismicity in Taiwan using groundwater level data and
GNSS time series. In western Taiwan, the seismicity rate reaches peak levels in February-April and drops to its lowest values in July-September, exhibiting a direct correlation with annual water unloading. The elastic hydrological load cycle may be
the primary driving mechanism for the observed synchronized modulation of earthquakes, as also evidenced by deep earthquakes in eastern Taiwan. However, shallow earthquakes in eastern Taiwan (<18 km) are anti-correlated with water unloading, which is
not well explained by either hydrological loading, fluid transport or pore pressure changes, and suggests other time-dependent processes. The moderate correlation between stacked monthly trends of large historic earthquakes and present-day seismicity
imply a modestly higher seismic hazard during the time of low annual hydrological loading. |
| Summary | (Plain Language Summary, not published)
We analyze detailed seismicity and hydrological data in Taiwan to delineate possible correlation between the two phenomena. We discover clear evidence of
modulation between the level of seismicity and hydrological loading. In western Taiwan, the seismicity rate reaches peak levels in February-April and drops to its lowest values in July-September, exhibiting a direct correlation with annual water
unloading. In eastern Taiwan, shallow earthquakes are anti-correlated with water unloading, suggesting other time-dependent processes. We also find moderate correlation between stacked monthly trends of large historic earthquakes and present-day
seismicity. Our results imply that the seismic hazard can be modestly higher during dry seasons. |
| GEOSCAN ID | 328055 |
|
|