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.
Puyehue-Cordón Caulle
Two days after the main shock of the 1960 Valdivia earthquake, the largest earthquake recorded in history, Cordón Caulle erupted. The eruption was believed to have been caused by the earthquake. The earthquake had struck the whole of Chile between Talca (30°S) and Chiloé (43°S) and had an estimated moment magnitude of 9.5. Being located between two sparsely populated and by then isolated Andean valleys the eruption had few eyewitnesses and received little attention by local media due to the huge damages and losses caused by the main earthquake. The eruption was fed by a long and north west-west (N135°) trending fissure along which 21 individual vents have been found. These vents produced an output of about 0.25 km³ DRE both in form of lava flows and tephra.