Anomalous decrease in groundwater radon before 2016 M_w 6.4 Meinong earthquake and its application in Taiwan

Area of Science:

• Geophysics
• Environmental Science
• Seismology

Background:

• Recurrent groundwater radon anomalies were observed at Paihe spring (P1) in southwestern Taiwan.
• These anomalies occurred prior to the M_w 6.3 Jiasian (2010) and M_w 6.4 Meinong (2016) earthquakes.

Purpose of the Study:

• To investigate the correlation between groundwater radon anomalies and seismic events.
• To assess the potential of using radon as a tracer for earthquake warning systems.

Main Methods:

• Monitoring groundwater radon concentrations at Paihe spring.
• Analyzing radon concentration data in relation to earthquake occurrences.
• Corroborating findings with seismic data and epicenter distances.

Main Results:

• Groundwater radon concentrations at Paihe spring showed significant precursory declines before both the 2010 Jiasian and 2016 Meinong earthquakes.
• Radon levels dropped from background concentrations to minima prior to each event.
• The Paihe spring, located near the earthquake epicenters, demonstrated its utility as a natural strain meter.

Conclusions:

• The study corroborates that small fractured aquifers can serve as effective natural strain meters.
• Radon anomalies in groundwater can be utilized as a tracer for earthquake warning in southwestern Taiwan.
• Long-term monitoring of precursory declines in groundwater radon offers valuable data for forecasting local earthquakes.