Massive earthquake in Italy

[shipps]

Per CNN unable to get link. Feared 100's may be dead.

[ChiSox_Sonix]

http://www.msnbc.msn.com/id/30061140?GT1=43001

 

6.3 magnitude

[farmteam]

Thought this part of that msnbc article was interesting...

 

Weeks before the disaster, an Italian scientist had predicted a major quake around L'Aquila, based on concentrations of radon gas around seismically active areas.

 

Seismologist Gioacchino Giuliani was reported to police for "spreading alarm" and was forced to remove his findings from the Internet.

 

Civil Protection reassured locals at the end of March that tremors being felt were "absolutely normal" for a seismic area.

[FlaSoxxJim]

Thought this part of that msnbc article was interesting...

 

Yeah, the connection between measurable radon anomalies and pending quakes is interesting. Some researchers have called it quackery and others recognize a connection but don't know how realistic or useful monitoring would be. I expect Balta can chime in and give us the skinny on the actual importance of the relationship.

 

Lots of beautiful old buildings lost in this quake though, that's for sure.

[Balta1701]

Yeah, the connection between measurable radon anomalies and pending quakes is interesting. Some researchers have called it quackery and others recognize a connection but don't know how realistic or useful monitoring would be. I expect Balta can chime in and give us the skinny on the actual importance of the relationship.

The problem with saying that earthquake swarms are going to be a precursor to a larger event is that it's a crapshoot. In some cases, a swarm of smaller events can certainly presage or even cause a larger event. On the other hand, a swarm of smaller events can actually wind up releasing some of the stress and could delay a larger event if a fault was primed for one. Couple random examples...the fault system that creates the San Andreas produced an earthquake swarm in the Cerro Prieto area of Northern Mexico but it never produced anything larger than a magnitude 5 event in that case. There's been a bizarre earthquake swarm near Reno for the last year or so, but again, nothing larger. About 2 weeks ago an earthquake swarm started on the Southern part of the San Andreas in the Salton Sea area (we actually had a class out there at the time) and it made some noise in the press & local fire departments were notified, but so far nothing. 3 months from now that segment could break and it could be directly related to them, the fault could sit idle for 20 years and then go with no warning, or the fault could rupture at some other point tomorrow and it might not have anything to do with that swarm.

 

If you run around saying that a swarm is a precursor to a larger event, especially if you're familiar with a fault, there's going to be a reasonable chance you'll be right, but there's probably a much larger chance you'll be wrong.

[kapkomet]

The problem with saying that earthquake swarms are going to be a precursor to a larger event is that it's a crapshoot. In some cases, a swarm of smaller events can certainly presage or even cause a larger event. On the other hand, a swarm of smaller events can actually wind up releasing some of the stress and could delay a larger event if a fault was primed for one. Couple random examples...the fault system that creates the San Andreas produced an earthquake swarm in the Cerro Prieto area of Northern Mexico but it never produced anything larger than a magnitude 5 event in that case. There's been a bizarre earthquake swarm near Reno for the last year or so, but again, nothing larger. About 2 weeks ago an earthquake swarm started on the Southern part of the San Andreas in the Salton Sea area (we actually had a class out there at the time) and it made some noise in the press & local fire departments were notified, but so far nothing. 3 months from now that segment could break and it could be directly related to them, the fault could sit idle for 20 years and then go with no warning, or the fault could rupture at some other point tomorrow and it might not have anything to do with that swarm.

 

If you run around saying that a swarm is a precursor to a larger event, especially if you're familiar with a fault, there's going to be a reasonable chance you'll be right, but there's probably a much larger chance you'll be wrong.

What about radon gas before the earthquake? I think that is what this scientist was basing his "predictions" on as well as the swarms. Is there any link?

[Balta1701]

What about radon gas before the earthquake? I think that is what this scientist was basing his "predictions" on as well as the swarms. Is there any link?

Same deal. The radon gas releases would happen because of just about any shift in the fault happening in certain types of rocks. Just did a bit of googling, and it really does depend on the fault. Some faults, 50% of the events might be proceeded by a radon spike. In others, 10-20%. In others, meteorology determines it a lot more. I'd be surprised if any area having an earthquake swarm didn't show a radon release spike. The gas is produced by radioactive decay, and is released by the breaking/crushing/heating of rocks, which happens any time even a small event occurs.

 

The issue is, if you think there's a 20% chance of a major earthquake happening in the next 3 months, what do you do? Right now, the Southern San Andreas is probably at a heightened risk, compared to the 2% a year or so chance we've estimated, given that there's an active swarm happening now. But what can you do? We don't know how to evaluate the probabilities that well at all, and we certainly can't put a date on when things will happen. Should we have evacuated these cities and kept them empty for months? Should everyone have been living in tents? Should we be evacuating L.A. right now because of what the San Andreas is doing right now?

[NorthSideSox72]

Same deal. The radon gas releases would happen because of just about any shift in the fault happening in certain types of rocks. Just did a bit of googling, and it really does depend on the fault. Some faults, 50% of the events might be proceeded by a radon spike. In others, 10-20%. In others, meteorology determines it a lot more. I'd be surprised if any area having an earthquake swarm didn't show a radon release spike. The gas is produced by radioactive decay, and is released by the breaking/crushing/heating of rocks, which happens any time even a small event occurs.

 

The issue is, if you think there's a 20% chance of a major earthquake happening in the next 3 months, what do you do? Right now, the Southern San Andreas is probably at a heightened risk, compared to the 2% a year or so chance we've estimated, given that there's an active swarm happening now. But what can you do? We don't know how to evaluate the probabilities that well at all, and we certainly can't put a date on when things will happen. Should we have evacuated these cities and kept them empty for months? Should everyone have been living in tents? Should we be evacuating L.A. right now because of what the San Andreas is doing right now?

Meteorology? The weather effects tectonic or volcanic changes?

 

[Balta1701]

Meteorology? The weather effects tectonic or volcanic changes?

At some level, yes. Changes in atmospheric pressure can affect how rapidly the planet degasses. You have a rainy day or a low/high pressure day and that can actually change the rate of radon coming out of the ground. Probably isn't significant enough to drive changes in much of anything other than degassing, it's usually not going to trigger a fault, but when you get beyond that...there are fairly well established correlations between earthquake occurrence and the tidal cycle, for example.

[kapkomet]

At some level, yes. Changes in atmospheric pressure can affect how rapidly the planet degasses. You have a rainy day or a low/high pressure day and that can actually change the rate of radon coming out of the ground. Probably isn't significant enough to drive changes in much of anything other than degassing, it's usually not going to trigger a fault, but when you get beyond that...there are fairly well established correlations between earthquake occurrence and the tidal cycle, for example.

Was there some relationship of tidal cycle that had something to do with the tsunami three years ago? I remember hearing something about that but can't quite remember the details... something about those deep sea earthquakes occur much more frequently on the tidal cycle (pull of moon is greater).

 

[Balta1701]

Was there some relationship of tidal cycle that had something to do with the tsunami three years ago? I remember hearing something about that but can't quite remember the details... something about those deep sea earthquakes occur much more frequently on the tidal cycle (pull of moon is greater).

There was a big study done on the aftershocks of those quakes in Indonesia and their tidal cyclicity. I'll just copy the abstract:

The frequency of earthquake incidence along the Andaman/Sunda/Java Trench plate-boundary region has been investigated for the ten-lunar-month period 28 October 2004–19 August 2005, encompassing the 26 December 2004 earthquake. During this period variations in earthquake activity correlate with the tidal-force cycles: maxima in earthquake activity occur around the times of new and full moons, typically lagging by 0–3 days. This relationship is consistent with earthquake inducement via ocean tidal loading. Also, during this period the earthquake incidence associated with new and full moons at the western end of the region was (a) 38% and (B) 86% higher than the period averages for the full and declustered major-earthquake catalogs respectively.

Basically, that means that there was a strong pulse of events above the normal level associated with that time.

[kapkomet]

That's been almost 5 years ago? Time flies.