Induced seismicity in Basel
The largest event prompted concern from local residents. The six borehole seismometers installed near the Basel injection well to monitor the natural background seismicity and the geothermal stimulation recorded more than 13,500 potential events connected with the geothermal project, from which 3,124 were of sufficient quality to permit [hypocenter] determinations in the period 2–12 December 2006, which spanned the main stimulation and the decline in the event rate. During the post-stimulation period from 13 December 2006 onward, a further 350 locatable events were detected up to 2 May 2007, by which time events were occurring sporadically at around one per day. In all, locations for more than 3,500 events were determined.
1981 Dawu earthquake
China has an extensive history of catastrophic earthquakes that ranges back to 1290. The first verified earthquake took place in Chih-li, killing roughly 100,000 people. The next great earthquake was probably the 1556 Shaanxi earthquake, the most devastating earthquake of all time. Roughly 830,000 were killed by the event. Other earthquakes in 1917, 1918, 1920, 1923, 1925, 1927, 1931, 1932, 1933, 1948, 1950, 1966, 1969, 1970, 1974, 1975, 1976 each killed at least one thousand people. Since 1981, earthquake fatalities have diminished greatly, though have not been stopped. As recently as 2008, an earthquake in Sichuan killed nearly 90,000 people.