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+--- Thread: M7.3 Nepal - yes, another one (/showthread.php?tid=247)
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M7.3 Nepal - yes, another one - Skywise - 05-12-2015
http://earthquake.usgs.gov/earthquakes/eventpage/us20002ejl
Judging by the epicenter of this one in relation to the epicenter and finite fault model (shown below) of the quake two weeks ago, I'd say this is a "cascade failure".
As of this writing, there is no FFM for this quake, but the focal mechanism is consistent with another thrust. I expect the new FFM to fill an area to the east of the previous fault model.
The image below is the finite fault model of the M7.8 on April 24th, not this new quake.
Although this was 'only' and M7.3, the region is already so damaged that the result could be just as devastating.
Brian
![[Image: 20002926_basemap.png]](http://earthquake.usgs.gov/realtime/product/finite-fault/us20002926/us/1429969841288/web/20002926_basemap.png)
RE: M7.3 Nepal - yes, another one - KathyKeegan - 05-12-2015
http://quakes.globalincidentmap.com/
RE: M7.3 Nepal - yes, another one - Island Chris - 05-12-2015
The Summary is informative:
http://earthquake.usgs.gov/earthquakes/eventpage/us20002ejl#general_summary
The focal mechanism is for a nearly flat fault. I think the previous one was pretty flat. This is the plate boundary between India and Eurasia. See the cross sections I posted a couple of weeks ago. I'm really interested in flat faults that have major or great quakes in a continental collision. That is because there is a local collision into what has been called the "Big Bend" of the San Andreas fault, causing mountains like the San Gabriels, Santa Ynez, San Rafael. There is no shortage of flat faults in southern California from pre-19 million year (Ma) subduction and then 19 Ma-5 Ma (younger in south) extension. Quite a bit of this is not in California hazard models. On the other hand, the geology is not very similar to Nepal.
At the time of the M7.8 Nepal, there was some concern that the fault had not ruptured nearly as far south as the outcropping fault. Today's quake is to the east of the previous one, not the south.
Chris
RE: M7.3 Nepal - yes, another one - KathyKeegan - 05-12-2015
(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
RE: M7.3 Nepal - yes, another one - KathyKeegan - 05-12-2015
(05-12-2015, 11:10 AM)Island Chris Wrote: The Summary is informative:
http://earthquake.usgs.gov/earthquakes/eventpage/us20002ejl#general_summary
The focal mechanism is for a nearly flat fault. I think the previous one was pretty flat. This is the plate boundary between India and Eurasia. See the cross sections I posted a couple of weeks ago. I'm really interested in flat faults that have major or great quakes in a continental collision. That is because there is a local collision into what has been called the "Big Bend" of the San Andreas fault, causing mountains like the San Gabriels, Santa Ynez, San Rafael. There is no shortage of flat faults in southern California from pre-19 million year (Ma) subduction and then 19 Ma-5 Ma (younger in south) extension. Quite a bit of this is not in California hazard models. On the other hand, the geology is not very similar to Nepal.
Just to tie it in, is there any watch on possible volcanic activity on the Mid India Ridge?
At the time of the M7.8 Nepal, there was some concern that the fault had not ruptured nearly as far south as the outcropping fault. Today's quake is to the east of the previous one, not the south.
Chris
RE: M7.3 Nepal - yes, another one - KathyKeegan - 05-12-2015
Now, how did I manage that.
My question decided to insert into the quote.
Is there any volcanic activity watch on the Mid Indian Ridge going on?
RE: M7.3 Nepal - yes, another one - KathyKeegan - 05-12-2015
I have decided one thing...
Indian news services have the collective IQ of a Muscovy duck. Someone in Nepal cast his eyes towards the heavens. Hopefully just looking at them. And 2 film stars ran around outside. I'm proud of them.
The rest of the 4 foot long site I just waded through was even less relevant, except for the story headers. It quacked a couple of times about 7.4, then babbled into nonsense. Hopefully when they get over the shock of a film star running around in his underwear in the afternoon they will tell us more.
context to global activity? - Island Chris - 05-12-2015
Hi Kathy,
I really can't evaluate your posts about global activity. There are always earthquakes and volcanic activity somewhere. Any way you can put any of this in context? Otherwise, it's kind of like background noise to me. There are some things that are obvious and understood: this Nepal quake is related to the previous one. And some things that are less obvious but logically related: the swarm of M7+ quakes in New Britain (Papua New Guinea) followed by M7+ a couple hundred km to southeast.
Chris
RE: M7.3 Nepal - yes, another one - Island Chris - 05-12-2015
Leonardo Seeber and John Armbruster of Lamont-Doherty Earth Observatory got on a plane with seismometers the day after the 1999 Izmit earthquake, and unlike everyone else, put the instruments up near the west end of the rupture. They then recorded a 3D history (=4D) of seismicity leading to the following M7+ Duzce. This is published somewhere.
I suspect there was some precursor for today's earthquake. The question is whether the area is instrumented enough to see it (or whether foreshocks, if any, were large enough). I wonder if anything could be seen from satellite data.
Is of interest to other areas including southern California. For example, there was discussion 20 years ago about a big San Andreas earthquake rupturing together with the Sierra Madre (oblique?) thrust, as some sort of worst case. There could be a delay between quakes of hours, months, decades. So, the question would be, when the big central San Andreas quake occurs, do you do anything about possible triggered/delayed events? Lower reservoir levels? Wait, there is little water in the reservoirs. I think you might only do something if there was some pattern of seismicity or other things....but in next decades you probably will still not know what is coming.
Chris
RE: M7.3 Nepal - yes, another one - KathyKeegan - 05-12-2015
I'm just coming up with an idea.
Historically, (admittedly way prehistorically) you have the Deccan traps rather close by. You can't really disregard volcanic activity as having a lot to do with earthquake activity. One reason for quakes would be upwellings of magma from hot spots in the crust, releasing pressure would trigger eruptions which would trigger quakes and so on. I'm not saying it right. You can't really separate them. It all goes back to the old "the gods are angry". I suppose I could wander over to the local university (U of South Florida) and see if they had anyone wandering the halls with a clue. That's a good 30 mile trip by city bus, since I'm not allowed to drive on these stinking pills the docs have me on.