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+--- Thread: M7.3 Nepal - yes, another one (/showthread.php?tid=247)
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RE: M7.3 Nepal - yes, another one - Island Chris - 05-12-2015
Hi Kathy,
save the bus ride. There are a few of us here who can answer questions. I am a research geologist and faults and folds is a lot of what I do. And, no, the Deccan traps have nothing directly to do with this. 65 million years is a long time. It is well understood, simply a fact, that India is converging with Eurasia at several cm/year and is being underthrust.
Chris
RE: M7.3 Nepal - yes, another one - Skywise - 05-12-2015
(05-12-2015, 11:15 AM)KathyKeegan Wrote:(05-12-2015, 11:07 AM)KathyKeegan Wrote: http://quakes.globalincidentmap.com/And the hits keep on coming. Bunches more aftershocks. The mid India ridge is going to town.
The volcano eruptions going on right now are flexing plenty of muscle.
Here's from the Smithsonian...
Activity
Axial Seamount Juan de Fuca Ridge New
Bulusan Luzon (Philippines) New
Calbuco Chile New
Dempo Indonesia New
Karangetang [Api Siau] Siau Island (Indonesia) New
Kilauea Hawaiian Islands (USA) New
Tungurahua Ecuador New
Ubinas Peru New
Aira Kyushu (Japan) Ongoing
Asosan Kyushu (Japan) Ongoing
Chirinkotan Kuril Islands (Russia) Ongoing
Chirpoi Kuril Islands (Russia) Ongoing
Colima Mexico Ongoing
Dukono Halmahera (Indonesia) Ongoing
Karymsky Eastern Kamchatka (Russia) Ongoing
Manam Papua New Guinea Ongoing
Popocatepetl Mexico Ongoing
Ruapehu North Island (New Zealand) Ongoing
Sheveluch Central Kamchatka (Russia) Ongoing
Shishaldin Fox Islands (USA) Ongoing
Turrialba Costa Rica Ongoing
Villarrica Chile Ongoing
Zhupanovsky Eastern Kamchatka (Russia) Ongoing
Other than happening to occur on the same planet, these events don't really have any direct, or likely even indirect relation to the Nepal quakes (or to each other?).
Once you start getting even a hundred kilometers away from a seismic event the relationship between two locations becomes quite small. When you start talking hundreds or even thousands of kilometers, the relationship is pretty much nil. The only causal connection is that they are all caused by plate tectonics. But the individual events have nothing to do with each other.
An analogy might be traffic accidents on freeways. A pileup on the 405 through the Sepulveda pass in LA (which seems inevitable) isn't going to have any effect on traffic on the same 405 as it passes by John Wayne Airport in Santa Ana, much less what's happening on the 5 passing Disneyland, or anything at all in Vegas, Denver, or Boston. This despite the fact they are all freeways and connected such that you can drive from one to the other.
Brian
RE: M7.3 Nepal - yes, another one - Island Chris - 05-12-2015
Hi Brian,
while I would like Kathy to filter the information she supplies more, I think there is at least a minor influence of Great quakes (and maybe high-end Major quake) at great distances. For example, seismic waves from Denali in Alaska I think is known to have triggered small quakes in the continental USA. Great quakes, and especially M9 quakes, ring the earth like a bell (free earth oscillations). I suppose the effect of this for triggering is extremely weak or nil. It has been a long time since I looked at this, but I recall there that there were two M8+quakes on the same day in 1905 (?). Yes, I know, statistics of small numbers.
With work by Roger, about a decade ago we looked into whether there is triggering at certain angular distances. The answer seemed to be "no" although there was something that I recall stood out a little bit at something like 103 (?) degrees. This investigation was related to Lowell Whiteside's Ph.D thesis.
Chris
RE: M7.3 Nepal - yes, another one - Skywise - 05-12-2015
(05-12-2015, 09:04 PM)Island Chris Wrote: ...
I think there is at least a minor influence of Great quakes (and maybe high-end Major quake) at great distances. For example, seismic waves from Denali in Alaska I think is known to have triggered small quakes in the continental USA.
True. I seem to recall places like Yellowstone and/or Mammoth had a noticeable uptick in seismic activity coincident with the passing seismic waves. But these are small effects.
If the passing waves of a large quake triggered a large quake elsewhere, wouldn't it be true that the triggered quake was probably about to go anyway? Camel backs and straw and all that?
Of course, the larger the quake, the larger the possible influence.
sigh... too bad seismology is so young compared to the geology. Can you imagine if we even had 1000 years of data at today's quality? We could probably predict quakes usefully by then.
Brian
RE: M7.3 Nepal - yes, another one - Island Chris - 05-13-2015
Brian,
what I forgot to say is that I don't think that seismologists/earthquake geologists know when a tiny quake will cascade to a big one. So, presumably if you can trigger a M2 by passing seismic waves, then you can trigger a M7 or whatever. It would just be rare, because most small quakes are just that. To trigger a 7 it would really have to be ready to go, and not have been already set off by some other stronger effect.
Chris
RE: M7.3 Nepal - yes, another one - KathyKeegan - 05-14-2015
(05-12-2015, 07:47 PM)Skywise Wrote:(05-12-2015, 11:15 AM)KathyKeegan Wrote:(05-12-2015, 11:07 AM)KathyKeegan Wrote: http://quakes.globalincidentmap.com/And the hits keep on coming. Bunches more aftershocks. The mid India ridge is going to town.
The volcano eruptions going on right now are flexing plenty of muscle.
Here's from the Smithsonian...
Activity
Axial Seamount Juan de Fuca Ridge New
Bulusan Luzon (Philippines) New
Calbuco Chile New
Dempo Indonesia New
Karangetang [Api Siau] Siau Island (Indonesia) New
Kilauea Hawaiian Islands (USA) New
Tungurahua Ecuador New
Ubinas Peru New
Aira Kyushu (Japan) Ongoing
Asosan Kyushu (Japan) Ongoing
Chirinkotan Kuril Islands (Russia) Ongoing
Chirpoi Kuril Islands (Russia) Ongoing
Colima Mexico Ongoing
Dukono Halmahera (Indonesia) Ongoing
Karymsky Eastern Kamchatka (Russia) Ongoing
Manam Papua New Guinea Ongoing
Popocatepetl Mexico Ongoing
Ruapehu North Island (New Zealand) Ongoing
Sheveluch Central Kamchatka (Russia) Ongoing
Shishaldin Fox Islands (USA) Ongoing
Turrialba Costa Rica Ongoing
Villarrica Chile Ongoing
Zhupanovsky Eastern Kamchatka (Russia) Ongoing
Other than happening to occur on the same planet, these events don't really have any direct, or likely even indirect relation to the Nepal quakes (or to each other?).
Once you start getting even a hundred kilometers away from a seismic event the relationship between two locations becomes quite small. When you start talking hundreds or even thousands of kilometers, the relationship is pretty much nil. The only causal connection is that they are all caused by plate tectonics. But the individual events have nothing to do with each other.
An analogy might be traffic accidents on freeways. A pileup on the 405 through the Sepulveda pass in LA (which seems inevitable) isn't going to have any effect on traffic on the same 405 as it passes by John Wayne Airport in Santa Ana, much less what's happening on the 5 passing Disneyland, or anything at all in Vegas, Denver, or Boston. This despite the fact they are all freeways and connected such that you can drive from one to the other.
Brian
That does hold true, in most circumstances. But I don't believe it is entirely circumstantial that so many volcanic events popped up right after the first Nepal quake. The pressures from magma below have to play a role. I don't recall the volcanoes on Sumatra doing much before Nepal, at least not actually erupting. If they did, well you have access to much better data.
I've only recently been well enough to start focusing on much more than myself. When I had the first seizure I was on life support for 5 days, and wasn't home for more than 6 months.
RE: M7.3 Nepal - yes, another one - Skywise - 05-14-2015
(05-14-2015, 01:06 AM)KathyKeegan Wrote: ...
I don't believe it is entirely circumstantial that so many volcanic events popped up right after the first Nepal quake. The pressures from magma below have to play a role. I don't recall the volcanoes on Sumatra doing much before Nepal, at least not actually erupting. If they did, well you have access to much better data.
I don't follow volcanoes much, but I think I know enough to say that volcanic activity that far from the quake makes it unlikely for there to be a causal connection. On the other hand, if there were volcanoes in Nepal and those started erupting, then yes there was probably an influence from the quakes.
I seem to recall off the top of my head of a volcano or two in Chile erupting after a particularly large quake down there.
Brian
RE: M7.3 Nepal - yes, another one - KathyKeegan - 05-14-2015
I learned differently. I am not formally schooled in earthquakes. I'm more school of hard knocks.
I distinctly remember having tremors just after the big Alaska quake in 64, way southwest of it on Okinawa. It was quiet there until just after that. I believe we also had the pretty much quiet dormant volcanoes on Okinawa puff a little smoke. Not much, but it did spark my interest.
Try not to discourage me too much.