Characteristics of Seismicity in the Areas of Large Water Reservoirs and Waterfalls: The Role of Effects from Additional Load and Permanent Vibration

Resumo

The characteristics of seismicity in the near vicinity of five large water reservoirs and three large waterfalls from different regions of the Earth are considered. It is found that in some cases induced seismicity manifests itself during the filling of reservoirs at quite large depths: in the lower crust and even in the upper mantle. There is negative correlation between the maximum magnitudes Мmax of the earthquakes recorded near water reservoirs and waterfalls and the water discharge in these objects (V_p). The largest values of М_max are characteristic of earthquakes that occurred near Sarez Lake (Tajikistan) and the Koyna Reservoir (India), which have the lowest V_p; in contrast, the smallest magnitudes are reported for earthquakes in the areas of the Khone Falls (Laos) and Niagara Falls (United States, Canada), where there are no large artificial water reservoirs, but huge water discharge takes place. The available data indicate that permanent vibration caused by falling water reduces the level of seismicity.