July 29, 2013 – NEW ZEALAND - A ‘‘severe’’ quake this - TopicsExpress

July 29, 2013 – NEW ZEALAND - A ‘‘severe’’ quake this morning in Cook Strait caused damage and was felt as far away as Auckland. It also increased the probability of further severe aftershocks, GeoNet seismologist John Ristau said. Did this morning’s quake cause any damage for you? The 5.4-magnitude quake struck at 1.07am today, just over a week since a 6.5 magnitude Cook Strait earthquake, which caused damage around Wellington. Today’s quake was 12km deep and 20km east of Seddon in Cook Strait. It was followed by a swarm of smaller quakes. More than 1500 people, mainly in the upper South Island and lower North Island, reported feeling the quake to GeoNet. At least one person reported it caused damage. ‘‘I certainly wouldn’t be surprised if this earthquake knocked items off shelves,’’ Dr Ristau said. It was also felt in Auckland, Hamilton, and Tauranga. At midday yesterday, Geonet had downgraded the chance of a 5-5.9 aftershock within 24 hours to 11 per cent. When GeoNet reworked its figures, it would increase the likelihood of a 5-5.9 aftershock, he said. –Stuff Switzerland’s volatile geological forces awakened by drilling: Switzerland’s ambitious energy plans were recently disrupted by a 3.6 magnitude earthquake in St Gallen. The quake was caused by a geothermal drilling project, which has temporarily been halted pending further investigation. The Swiss Seismological Service measured a total of 400 seismic shocks following a failed bore hole test. Geothermal energy carries certain seismic risk, according to Swiss Seismological Service’s director Professor Stefan Wiemer: “We understand that most of the occurring seismic shocks are small. The big problem is to evaluate in such an environment the probability of a bigger, harmful quake. We can’t unfortunately completely exclude that.” Seismic activity due to Geothermal drilling has been frequently reported elsewhere in the world, as can be seen from cracks in the ground that appeared in the German town of Staufen. This seems to be one of the unavoidable disadvantages of obtaining renewable energy from the ground. The trick is to drill deep enough and pump water at 140°C or higher that can be used for heating or power. Geothermal drilling in late 2006 and early 2007 near Basel caused a series of earthquakes, some greater than magnitude 3, leading to the scrapping of the project to build Switzerland’s first geothermal plant. Former mayor Erwin Knapek is the founder of a project in Munich. He believes all energy producing systems carry risks. “We certainly have to live with the risk of seismic shocks. Most of them will go unnoticed. And slightly bigger ones, so far, with magnitudes up to 3.4 or 3.6 haven’t caused any destruction. This is the risk we have to accept with each drilling,” Knapek said. According to experts, the potential for geothermal electricity production in Switzerland is very high. In 2011, the Swiss parliament voted to close the country’s nuclear reactors by 2034, forcing a search for alternatives. Geothermal research and testing is one of them. But the recent earthquake has raised new concerns about safety, costs and its feasibility. -Euro News