[News] 6.2 Earthquake in central Italy
- Thread starter DarkAudit
- Start date
Man, some of those pics are scary.
We were hit by a 6.4 earthquake earlier this year, and that caused buildings to collapse in southern Taiwan. And here in Taiwan, we take earthquakes into account when we construct our buildings. A place like Italy, with lots of old historic structures? It's gonna look like a warzone.
We were hit by a 6.4 earthquake earlier this year, and that caused buildings to collapse in southern Taiwan. And here in Taiwan, we take earthquakes into account when we construct our buildings. A place like Italy, with lots of old historic structures? It's gonna look like a warzone.
To be fair, Italy as well has a long history of plenty of earthquakes. Those Roman buildings have been around for quite a few.
Not to say this isn't bad, mind, but it's not like a sudden unexpected earthquake in, say, Germany would be. Italy has the highest amount of European volcanoes, after all.
Dave
Staff member
We've had 8 visits in the last month. So lurkers, mostly.
fade
Staff member
Friendly neighborhood geophysicist reminding everyone that there's a pretty big difference between 6.2 and 6.4. Richter scale numbers are logarithmic, meaning these are exponents. And base 32 exponents at that. So a 6.4 releases twice as much energy as a 6.2 (because 32^0.2 = 2).
Really? I mean, I knew they were logarithmic, but I didn't know it went up that fast. Man, makes those 9.2 earthquakes look a whole lot more scary than they already were.
fade
Staff member
Earthquake energy attenuates away from the focus (3D epicenter) pretty quickly, and damage doesn't scale linearly with energy release. Damage also depends greatly on construction techniques and the soil upon which buildings are constructed. Floodplain sediment, for example, sucks. It turns essentially into quicksand. Large buildings are built on steel piles driven to the bedrock, but when the sediment goes to jelly, the whole building becomes an upside down pendulum.
Tectonic plate movement energy gets out of hand pretty quickly using any slower logarithmic system. 6.0 is still no slouch, equivalent to the energy released for the Hiroshima atomic bomb. The scale was developed, though, more to give an idea of the frequency of similar events and the amount of damage that can be expected - and "total local destruction" had to be 10 or under.
https://en.wikipedia.org/wiki/Richter_magnitude_scale
So 10 is really the upper limit for possible natural tectonic causes, and a ten would require the entire series of faults along the pacific coast to rupture simultaneously. Anything beyond a 10 must necessarily involve an external source of energy, such as an asteroid impact. The impact that cost the dinosaurs their lives was estimated to be about a 13, and a 15 is probably enough to destroy the Earth completely.
fade
Staff member
Also, FYI, the Richter scale is primarily for export to media. It's not something we use regularly internally except as a quick gauge. It's not very informative for one thing (other than to say, wow that's big!). For another--and most people don't know this--the Richter scale is empirical and calibrated to southern California. It's based off of needle movement on old school seismometers.
That's what happened here.
This post reminded me of Tremors.