http://www.physorg.com/news89404840.html

Mr. Cayupi"s explanations as to the source of southern Chile"s recent many small tremors leaves more questions that answers. If the hypocenter has been located at a depth of 49 kilometers, where at there could be magma, How can he give as a posible source of the moderate earthquake of last 23 November a fracturing rock at a depth of 9 kilometers (six miles)?
2007 01 23 204018.89 -45.38 -71.98 49 5.00 mb GS (Source NEIC)
Also, How could the movement "result in a small submarine volcano"? The sea is at least 120 Km away from the epicenter...
Regards from the Nazca Plate Subduction Zone!

Famous last words.

These subduction zone volcanoes are the most explosive as the magma contains a lot of sea water. Watch this one!

The seismicity map at this link:

http://sismomundo.blogspot.com/

shows that the two moderate earthquakes so far are quite far from the interior seas of Chile and even the Hudson Volcano or the fiords mentioned in the article.
Regards from the Nazca Plate Subduction Zone

Aysen fjord. A fjord is a body of water with an underground water table and rivers. Mix water with magma in that area and it produces lots of superheated steam under great pressure which can explore any weaknesses in the rock strata above it (as in 1700 tremors). With 2,900 volcanoes in Chile, 500 of which are active, that sounds like the Earth's crust is thinner than normal at this point.

A moderate, intermediate depth, earthquake took place some 200 Kms north from the Aysen moderate earthquakes of the last three weeks, giving more weight to a disagreement with Mr. Cayupi's explanations about the Aysen increased activity.
DATE TIME LAT. LONG. DEPTH MAGNITUDE
2007 02 10 060304 -42.86 -71.43 161 Km 5.0 mb GS

Intermediate depth earthquakes don't take place ever so often at these latitudes, in fact in the last 35 years only two moderate (Magn > 5.0) and ten light (Magn > 4.0) have. Intermediate depth earthquakes have depths ranging from 85 Km to 175 Km, which is the depth at which volcanoes are believed to "source" their magma.

So, judging from seismicity analisys of the area, it seems to me that the Aysen recent activity maybe due to tectonic causes. A look back at the records shows that the "largest earthquake in the world" 1960 05 21 Big Earthquake, developed a rupture of over 1000 Km. heading south from its initial 7.3 Major Earthquake near Concepcion, at coordinates -37.50/-73.00 all the way south to the location, coordinates -45.50/-73.50, fifteen days later on 1960 06 06, a 6.9 Ms magnitude strong earthquake at a depth of 60 Km. some 40 kms from Hudson Volcano in Aysen. This 8.5 Ms Big Earthquakes (1960 05 22) sequence may have stopped in 1974, or not?

Rergards from the Nazca Plate Subduction Zone !

Does anyone have statistics on the frequency of earthquakes for the past say 50 to 100 years. I have searched the net, but found nothing

brupen,
What kind of data or for what area?
It is easy to find the data, only that data is incomplete for the years before 1973. Copied below are some notes on the subject:

"ABOUT THE NEED FOR A REVISION OF SEISMIC DATA RECORDS

It has become evident, in the course of seismic data analisys, that some of the data available is not up to date. Only the USGS/NEIC data registry for the years 1973 to present is reliable. Here follows some examples of the difficulties encountered which need to be addressed:

- Historic records beyond 1973 tend to be incomplete in two ways. First, there is no data registered for far away places, of doubtful interest, such as oceans where at nobody lived, and secondly there is no data registered for non significant earthquakes in places where at people lived. Thus, an earthquake count for a geographical grid search of South America, shows a great shortage of minor and moderate earthquakes for the years previous to 1970. For strong earthquakes, such shortage is evident beyond the year 1940 and for mayor and big earthquakes shortage is evident beyond the year 1900. Extra deep earthquakes, at depths of 550 Kms to 660 Kms were unknown to science before 1910 and this does not mean that there were no such earthquakes before.
- Some data in catalogs is incomplete. This kind of inconsistency has as a result, for example that the World’s Greatest Earthquakes (the southern Chile mainshock of 1960, a 9.5 magnitude earthquake) is not listed in the SISRA Catalog or/and that is not accounted for or listed in the Geographic Grid Search of the NEIC earthquakes search results. (You have to dig the data in some other way to get it)
- Some data in catalogs is most probably wrong. The SISRA catalog listing of event 1957 11 28 030755, a 5.80 mbIGP magnitude earthquake,at a depth of 600 Kms, is way off the subducting’s plate eastern limit at the posted location of -10.00 lat. -75.00 long."

In any case you can go to this link and learn how to get all the data you may need:

http://neic.usgs.gov/neis/epic/

Regards from the NPSZ!

p.s. the

http://sismomundo.blogspot.com/

has been updated with a seismicity map of the 1960 05 21 Big earthquake.sequence

A new moderate earthquake has taken place today, only 15 Kms away from the two previous ones, in the area of Aysen, southern Chile. The preliminary parameters of this new seism are:

DATE / TIME (UTC) / LAT. / LONG. / DEPTH / MAGNITUDE
2007 02 23 / 195549 / -45.26 / -72.02 / 24 Km / 5.60 mb GS

A few miles nearer to the surface, the magnitude of 5.60 mbGS makes it the strongest in may years in the area. The third moderate earthquake since Jan 23rd, a month ago, is still some 100 Kms from the Aysen fjord where at the seismic swarm has been located.

The seismicity map at:

http://sismomundo.blogspot.com/

has been updated.

Regards from the NPSZ!

what about last night ?? at 11.30 pm and at 3 am.... felt like the strongest one yet....

The seismicity map for Aysen province at the link:

http://sismomundo.blogspot.com/

has been updated.

The latest earthquake has been located some 50 Kms north of Puerto Chacabuco, at a depth of 35 Km, and a magnitude of 5.50 mbGS

Regards from the NPSZ!

It has been published the Session Information for the 2007 AGU's Joint Assembly in the following link:

http://start.org/cgi-bin/sessions5?meeting...43C&maxhits=400

On thurday afternoon, at 15:15 hrs, the paper "The Aysen (Southern Chile) 2007 Seismic Swarm: Volcanic or Tectonic Origin? by*D Comte, A Gallego, R Russo, V Mocanu, R Murdie, J VanDecar, will be presented.

Reading the abstract of this presentation one has the feeling that the chilean public, specially those inhabitants of tha Aysen Fiord surrounds, have not been informed by authorities in the manner they deserve; complaints about this lack of information have been many, and surely is the main theme of discussion in southern Chile. However, the above mentioned scientists seem to have a quite clear case of ¿MAGMA, SUBMARINE VOLCANO OR ACTIVE TECTONICS? presentation ready for the world, outside of Chile...
Oh yes, and "we are also so really poor and short of equipment", is the other theme that will surely be presented to the international audience.
Talk about .......!

Much regards from the Nazca Plate Subduction Zone!

6000 tremors, 8 light, and 4 moderate earthquakes, almost 90 days ater, the picture is getting clearer.
ACTIVITY SINCE SWARM
PDE-W 2007 01 23 204016.30 -45.31 -72.19 32 5.20 MLGUC 5F . .......
PDE-W 2007 01 24 025104.19 -45.30 -72.53 35 4.70 mb GS .F . .......
PDE-W 2007 01 28 025320.85 -45.16 -72.32 49 4.40 mb GS .. . .......
PDE-W 2007 01 31 080614.69 -45.19 -72.33 15 4.80 mb GS .. . .......
PDE-W 2007 02 03 090015.79 -45.24 -72.24 10 5.10 mb GS .. . .......
PDE-W 2007 02 20 002323 -45.33 -73.02 8 4.80 MLGUC 6F . .......
PDE-W 2007 02 21 002323 -45.33 -73.02 8 4.80 MLGUC .. . .......
PDE-W 2007 02 23 195548.60 -45.34 -72.32 25 5.60 mb GS 6F . .......
PDE-W 2007 02 23 223856.75 -45.33 -72.59 35 4.60 mb GS .. . .......
PDE-Q 2007 03 24 004534.01 -45.38 -74.17 10 4.40 mb GS .F . .......
PDE-Q 2007 04 02 024942.89 -45.22 -72.82 35 5.50 mb GS .. . .......
PDE-Q 2007 04 11 055040.18 -45.27 -73.06 10 4.70 mb GS .. . .......

The earhquakes sequence bears the east-west general disposition, while the tremors follow a south-north general direction. Activity previous to the begining of the swarm is mostly around the last and next to last transform fault of the Nazca/Antartic Rift. The Liñique-Ofqui fault shows a discontinuity just below the Aysen fiord.
Preliminary conclusion is that the swarm has a tectonic origin. The nazca plate easternly movement (shown by previous seismicity 2000-2006, then stop, then 2007 01 15, then swarm), the compression generated at a 90 degree angle on the Liñique-Ofqui fault discontinuity and the Aysen fiord water sipping down the cracks generated on the compressed material, could account for the south-north tremors and the east-west earthquakes.

ACTIVITY PREVIOIUS TO AYSEN SWARM
PDE 2000 01 10 233422.74 -45.23 -76.54 33 4.70 mb GS .. . .......
PDE 2000 01 13 105946.87 -45.79 -72.28 33 4.80 mb GS .. . .......
PDE 2000 02 14 092854.36 -45.76 -72.81 33 5.10 mb GS .. . .......
PDE 2000 02 14 213946.31 -45.79 -72.60 33 5.00 mb GS .. . .......
PDE 2000 06 18 171247.71 -45.67 -76.71 33 .. . .......
PDE 2000 06 21 071137.49 -45.79 -75.44 33 4.50 mb GS .. . .......
PDE 2001 07 08 194152.51 -45.76 -75.45 33 4.70 mb GS .. . .......
PDE 2001 11 14 235724.47 -44.92 -75.87 33 4.60 mb GS .. . .......
PDE 2001 11 18 104817.84 -45.52 -76.54 33 4.70 mb GS .. . .......
PDE 2001 12 29 041325.68 -44.94 -75.93 33 4.50 mb GS .. . .......
PDE 2001 12 30 050456.34 -44.84 -75.98 33 4.50 mb GS .. . .......
PDE 2002 01 10 232551.26 -45.74 -72.65 33 4.80 mb GS .. . .......
PDE 2002 01 29 110303.14 -45.08 -75.77 33 4.40 mb GS .. . .......
PDE 2002 03 03 064824.46 -45.51 -76.31 10 4.30 mb GS .. . .......
PDE 2002 03 03 071615.69 -45.84 -76.12 10 5.90 MwGS .. M .......
PDE 2002 03 03 115710.96 -45.72 -75.68 10 5.40 mb GS .. . .......
PDE 2002 06 05 232341.86 -45.93 -72.69 33 4.50 mb GS .. . .......
PDE 2002 08 16 072225.59 -46.17 -75.50 33 4.50 mb GS .. . .......
PDE 2003 06 20 042328.44 -45.57 -75.94 33 5.40 MwHRV .. M .......
PDE 2003 09 14 123711.95 -46.77 -74.63 33 4.40 mb GS .. . .......
PDE 2004 11 04 081017.87 -45.92 -76.55 25 5.00 MwHRV .. M .......
PDE 2004 11 04 082916.58 -45.90 -76.44 25 5.30 MwHRV .. M .......
PDE 2005 02 10 175945.85 -45.72 -75.78 35 4.50 mb GS .. . .......
PDE 2005 03 30 075524.54 -45.63 -76.73 25 4.70 mb GS .. . .......
PDE 2005 07 08 051554.77 -45.82 -76.61 37 4.80 mb GS .. . .......
PDE 2005 10 10 160700.28 -45.62 -76.57 35 5.10 MwHRV .. M .......
PDE-W 2006 02 24 211457.37 -44.67 -75.54 10 4.80 mb GS .. . .......
PDE-W 2006 04 28 182154.96 -45.69 -76.25 10 4.90 mb GS .. . .......
PDE-W 2006 05 29 133942.12 -46.02 -76.17 10 4.40 mb GS .. . .......
PDE-W 2006 05 29 185621.08 -46.35 -75.09 10 4.50 mb GS .. . .......
PDE-W 2006 05 29 221950.89 -45.83 -75.85 10 4.10 mb GS .. . .......
PDE-W 2006 05 30 025009.85 -45.76 -75.52 36 5.60 MwHRV .. M .......
PDE-W 2006 06 25 162728.78 -46.69 -75.86 10 4.30 mb GS .. . .......
PDE-W 2006 09 21 044844.29 -44.21 -75.11 6 4.00 mb GS .. . .......
PDE-W 2006 10 07 163218.97 -45.70 -76.29 40 5.00 mb GS .. . .......
PDE-W 2007 01 15 175209.20 -45.76 -76.40 38 4.40 mb GS .. . .......

Once again I am able to observe a sequence stop-restart above. After 2000 06 21, a whole year of aquiescence, then Big Earthquake 2001 06 23 and the sequence restarts. After 2003 09 14 a whole year of aquiescence, then 2004 05 03 and 2004 06 15 are 6.5 Mw and 6.0 Mw at the begining of the Liñique Ofqui fault, then sequence restarts to today... Makes me more prone of believing in Remote Triggered Seismicity and the end of the chaos theory. (Same occurance at the Ubinas volcano crustal activity)

Access to the SEISMICITY MAPS and spanish text is on :

http://sismoaysen.blogspot.com/

Much regards from the NPSZ!

It had to happen, that is, this IS Chile:

A STRONG EARTHQUAKE MAGN. 6.20 Mw HAS TAKEN PLACE IN AYSEN, THE STRONGEST IN 45 YEARS!

Just s the Emergency Management Office (ONEMI) had on April 17th issued its "prediction" of QUOTE Onemi confirma que ola de sismos en Aysén está en retroceso Domingo 15 de Abril de 2007 17:42 ANSASANTIAGO.- La directora de la Oficina Nacional de Emergencia (ONEMI), Carmen Fernández, afirmó hoy que el fenómeno sísmico que afecta a la región de Aysén "está en retroceso".
y "descartó que "el enjambre sísmico que se vive en Aysén pueda generar un terremoto".
"Onemi confirms that seismic wave in Aysen is fading out" and "The Director of ONEMI discerded that the seismic swarm in Aysen could generate a destructive earthquake"

A new blogspot has been created to inform about this event at:

http://sismoaysen.blogspot.com/

The rest is only bad news...

Ok, i live in chile, so it's first hand info.
Last week a new earthquake occured in aysen and caused portions of mountain to fall to the see, thus causing a small tsunami that killed about 10 or 12 people (with a couple more missing). It was huge but in a not so populated area.
Now that people are dead all the problems with the government are arising, how they said nothing was going to happen, how the didn´t evacuate and hid information of international and local sysmic studies that said that indeed there was probably a volcano trying to come undrsea. This government sucks. But the studis have been publicated by now, and the government says nothing about them and just won't evacuate. The alst year since the lady president got elected this country is a chaos. It used to be very good, but all she does is not wrong, but stupid at the least. So they are trying to move the attention away of the "small mistake" they did teling people in aysen evrything was perfect...

Chilean Navy's sea floor survey report puts the lid on the "expert's" magmatic/volcanic cone origin of Aysen's swarm. The news, published yesterday, state that there are no cracks on the sea floor's surface and the fiord's bathymetry remains the same as surveyed in 2002.
News in spanish here:

http://www.lasegunda.com/ediciononline/cro...dnoticia=344311

"Experts" are now jumping on the "tectonic origin" wagon with a complete lack of self-respect.

Talk about...!

Much regards, from the NPSZ...

Well actually, just because there's no volcanic cone doesn't mean there's no magma underground. Anyway, the tectonic scenario seems more logical but I still think that it could be a combined process. We'll just have to wait and hope for better research on the subject.

Nice to see you're spreading the word Rafael.

Cheers to all from Peru.

Miguel,
So far, there is no evidence of magma either. Water temperature is the same no matter where it is measured, whether near the microseisms hypocenter or far away from the given location, as reported by Sernageomin in March 27th.
Regards, Rafael