Characteristic behavior of water radon associated with Wenchuan and Lushan earthquakes along Longmenshan fault

• Long trend of water radon measured in China during 2003–2014 at six stations round Longmenshan fault.
• Water radon shows characteristics behavior associated with Wenchuan and Lushan earthquakes.
• Water radon shows one to one relation with rainfall and ground water level variations.
• Sharp increase or decrease in water radon concentrations are found few days prior to the earthquake.

In China, numerous subsurface, surface water well and spring parameters are being monitored through a large network of stations distributed in China sponsored by China Earthquake Administration (CEA). All the data from these network is managed by China Earthquake Network Center (CENC). In this paper, we have used numerous data (water radon, gas radon, water level, water temperature) available through CENC for the period 2002–2014 and studied the behavior and characteristics of water 222radon [Rn(w)]. The observed parameters were also complemented by rainfall data retrieved from Tropical Rainfall Measuring Mission (TRMM) satellite. Our detailed analysis shows pronounced changes in the observed parameters (especially water and gas radon) prior to the earthquake. The changes in water radon, ground water level and rainfall showing characteristics behavior for Wenchuan and Lushan earthquakes. The long term data analysis of water radon and water level at various locations around epicenters of two major earthquakes along Longmenshan fault show a positive and negative relation of water radon and water level prior to these earthquakes. It is difficult to find any trend of water radon and changes in water radon pattern with these two earthquakes that could prove as a reliable precursor of earthquakes. Changes in the water radon concentrations from one location to other may be associated with the changes in ground water regime and geological settings in the epicentral and surrounding regions.