Wednesday, September 15, 2010

WILD TECTONIC FORCES

From New Zealand friends and contacts have come emails containing information about the Christchurch earthquake which caused damage estimated at $4billion. Of immense interest was the Christchurch Quake Map compiled by Paul Nicholls of the University of Canterbury Digital Map Group on http://www.christchurchquakemap.co.nz/ which provided a dramatic time lapse view of the earthquake , second by second, indicating the intensity and depth of the seismic swarm that followed . It is truly fortunate that there were no lives lost in the quake as it was as strong as the one that devastated Haiti. Many fine old buildings have had to be destroyed . There have been hundreds of aftershocks , some felt in the national capital, Wellington , and the economic impact on NZ will be enormous.

In the Canterbury Plains a 20kilometre long "hump" has been thrust up on farms and there is concern that aquifers used for irrigation have been filled in or disappeared. Silos were also knocked over on some farms.
Some relatives we had to lunch recalled being in Rabaul, Papua New Guinea, during strong shakes, one as powerful as the recent one in Christchurch, which bent the blades on fans in the hospital, a “whooshing” sound being heard as it struck . This reminded my wife that a similar sound, like a truck pounding along a road, was heard during a quake she experienced in South Australia.

Discussion on the earthquake in Christchurch resulted in a Darwin resident saying that when she was coming back on a yacht , which had taken part in a Darwin to Ambon yacht race , the vessel was hit by a huge wave in the Banda Sea, an area where many quakes are centred, which stove in the forecastle and was thought to have been generated by an undersea upheaval.

This morning an email arrived from the Magnetic Island Times online website with the interesting news that a $30,000 German seismometer buoy anchored in the deep Kermadec Trench , north of New Zealand ,keeping watch on seismic activity, has been found washed up on a beach south of Townsville ,Queensland .