> > But NZ had a magnitude 7.2 earthquake (being reported as a 7.4 on > > news) at 4:35am this morning our time. > I looked at the map, and the epicenter is pretty far inland, and not all > that close to Christchurch. It will be nothing like a 7.0 there, which i= s > something most properly designed (and inspected without payoff) buildings > should be able to take without major structural damage. > So what happened, a few 1000 finally took a shower? You probably / apparently don't follow earthquakes in detail. If it had been that mild I'd not have mentioned it. 30 km to the epicenter is "uncomfortably close" (and I have family members who were there who will back that up :-).) As I noted, the maps I reference showed the effective magnitude at various distances (NOT using the Richter scale), populations involved and probable damage levels. Damage in Christchurch was about what I'd expect from the reports and what = I reported in the original email - 'a bit more than a cold shower' [tm] in some cases. Amazingly, given the damage that was done in some areas, there were no reported deaths, but a few people did end up in critical care - mainly due to falling chimneys. Some fires due to gas main ruptures - including one caused by electricity restoration - caught by TV cameras. Original depth was reported as about 35 km - which is quite shallow and wel= l in the heavy damage range for a 7+ quake, but as the size was progressively downrated 7.4 7.2 7.0 as they refined their figures they brought the depth up to about 16 km which is VERY shallow. If you look at the shake maps and hazard maps they typically show a sever damage zone about 1 x depth radius out from the epicentre.. So Christchuch cioty at 30 km from epicentre was about 1 x depth as originally reported but 2 x depth as corrected. The shallower quake would cause more damage locally BUT less in Christchurch at 2 x depth away. A visiting US geology professor was very excited to wake up to his first bi= g quake. He rushed towards the epicentre while everyone else looked towards town. He reported (evening TV news) and uplift of about 1.5 metres observed worst case so far. Small compared to some. My nephew's old house, sold about 6 months ago, had the chimney fall and collapse the living room roof/ceiiling. My son woke to the quake, had bookcases fall and roofing tiles have split. His cold shower may come when it next rains :-0> They were talking about evacuating some suburbs due to lack of power/water/sewage but probably didn't so so. One two storey restaurant is now a one storey restaurant - the original 1st floor crumbled completely. "Paying off" of building inspectors is almost completely unknown here - thi= s is, after all, the least corrupt country in the world (really, apparently). Having people avoid permits etc is more common. We are also reasonably, but far from perfectly, earthquake aware as a tectonic plate edge runs up the spine of the whole of The South Island* ("proper name" fwiw) and half way u= p The North Island before turning at about 45 degrees at an active (usually sleeping) pair of volcanoes, just before the largest volcano on earth in th= e last 20,000 years, and and heading ~ NE out to sea via an offshore active volcano (less sleepy, only kills people very occasionally). * South Island spine is the Lord of the Rings impressive signal fire range and one of the North Island active volcanoes is the LOTR Mt Doom. (It's nowhere as active as it's shown in LOTR - you can descend into the crater i= f you wish and most who do live - danger is usually only asphyxiation - real eruptions only very occasional. not As noted, Tsunami was never a great likelihood. Equivalent energy in Megatons depends on what you read. Some sites put a 7.1 Richter quake at AN602 / Tsar bomba level (50 megaton) and others (with more figures but no guarantee of better accuracy of "only" 500 kiloton. I'd not want to have Tsar bomba or equivalent friend only 10 miles away straight down at detonation. miles LOOKs like he knows what he's talking about. (Looks) http://www.jclahr.com/alaska/aeic/magnitude/energy.txt At least its concise http://wiki.answers.com/Q/How_does_the_energy_released_by_an_earthquake_com= pare_to_the_energy_of_a_nuclear_weapon Tsar bomba DTTAH The story goes, probably apocraphyl that the US plane sent to monitor the bomb was closer to the bomb at detonation than the release plane was and that the US craft returned with scorched paint. Survival of the release plane was by no means certain. This also states (without source or derivation) that 50 Mt + Richter 7.1 equivalent. http://bit.ly/TsarBomba > It also looks like too far inland to make a decent size tsunami, and no good > place to send it anyway. There is practially nothing on the antarctic > peninsula, and not much more on the coast of Chile. .... and apparently haven't been to Chile either :-0. (Nor have I, yet). I have friends there who would beunimpressed with receiving our non-existent Tsunami. Russell --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .