January 17, 2013 – NEW ZEALAND – A magnitude-3.3 earthquake that struck Christchurch this afternoon could be the 11,000th tremor since September 4, 2010. The quake hit at 12.55pm, 15 kilometers east of Christchurch at a depth of 6km. Over 163 people reported feeling the “moderate” shake on the GeoNet website. According to Christchurch Quake Map, the quake was the 11,000th the region has experienced since the magnitude-7.1 struck early on September 4 2010. GNS Science geological hazard modeler Matt Gerstenberger said 11,000 quakes was a significant but expected number for the region to have experienced. “Anyone living there knows what it has been like. However, it is in the range of what we would have expected for a region which has had a large earthquake.” Many of those quakes would not have been felt, he said. “Many would have been so small they wouldn’t have been noticed. Also, I’m not sure what the minimum magnitude for a quake is that is mapped on that website, but that [11,000] figure would be in the range, I suspect.” He did not expect the number of quakes mapped to go up greatly. “According to the aftershock sequence, the aftershocks will now be further apart and so the number will go up slowly over time,” he said. “There won’t be a huge or sudden increase.” –Stuff.NZ
contribution Helen M.