[KathyKeegan]

I'm thinking what is happening east of New Guinea is a consequence of Nepal, along with a volcano heating up due to some plate shifting there. The shocks are moving vertically and got up into the 7 range. It may sit back and percolate some gas for a bit, But something is stirring the pot and Nepal probably changed the tensions horizontally. Some of those big shocks are close to 10 miles down. That seems very shallow. Good thing the population is low around that area. If something like that started going off near Sumatra it would be unreal.
You have to bear with me, I don't have the science background you wizards do. I've read up on it for years, so I understand you, but I'll have to get the language straight before I sound very technical.

[Island Chris]

I don't think Brian has a science degree either, but, like me, he has a well developed skepticism. For M.7 earthquakes, saying they are getting shallower does not mean much for the following reasons, unless you are talking about 500 km vs 10 km. That is because a M7 will break a wide range of depths. Probably the Tohoku (Japan) March earthquake broke from 30 or 40 km depth right to the sea floor (but very deep sea floor, maybe 7 km). The depth given is just the depth of initiation of a big rupture. They get this wrong all the time on TV/online. For example, the earthquake is 300 km away, when it actually ruptured to 100 km away.

Also, when you see a depth that is an even number, it usually means that they just tell the location program to use that, or an automatic system uses that.

You may know this, but if you click on a quake on the usgs map, it bring up more Click on scientific and for larger quakes, it will give you one or more focal mechanism solutions. Click on that and it will tell you more.

Chris

[Island Chris]

Someone told someone I know that there were a lot of volcanic eruptions before the Nepal earthquake. I am, of course, skeptical. This was posted on my acquaintances Facebook page, but I will not friend anyone besides my daughter, so could not get to it. The question is whether it was posted before or after the Nepal quake. If after, the media tend to report on related earth science stories.

I don't know whether there is any semi-quantitative way to look at the : Maybe the Smithsonian site and try eruptions vs time. But, eruptions can last a long time; for example, Hawaii: 32 years.

We do know that seismic waves from very large earthquakes can trigger small earthquakes in areas with big magma chambers like Long Valley California.
Chris

[KathyKeegan]

(05-08-2015, 11:05 AM)Island Chris Wrote: I don't think Brian has a science degree either, but, like me, he has a well developed skepticism. For M.7 earthquakes, saying they are getting shallower does not mean much for the following reasons, unless you are talking about 500 km vs 10 km. That is because a M7 will break a wide range of depths. Probably the Tohoku (Japan) March earthquake broke from 30 or 40 km depth right to the sea floor (but very deep sea floor, maybe 7 km). The depth given is just the depth of initiation of a big rupture. They get this wrong all the time on TV/online. For example, the earthquake is 300 km away, when it actually ruptured to 100 km away.

Also, when you see a depth that is an even number, it usually means that they just tell the location program to use that, or an automatic system uses that.

You may know this, but if you click on a quake on the usgs map, it bring up more Click on scientific and for larger quakes, it will give you one or more focal mechanism solutions. Click on that and it will tell you more.

Chris

I was talking about very to deep to getting close to the surface. Several early shocks I remember being up in the hundreds of K's deep. Now they seem to be sitting closer to 45 K's. At least they were when I was watching them yesterday. Fiji is playing in the 525 range deep.