Global Earthquake Explorer (GEE) Screenshots Thread, page 1

Originally posted by Shirakawa
No, sorry, I don't know if there are closer stations as I don't usually monitor that zone of the world. If you have tried adding all seismic network from Station Chooser in GEE and there wasn't any station close to the epicenter of the last big earthquake, then there's nothing you can do I'm afraid.

Closer stations probably do exist, but not on public networks accessible via GEE.

By the way, if a powerful enough earthquake occurs very close to a broadband seismometer (short band ones get easily saturated) you can easily see velocity readings exceeding several mm/s.

[edit on 2009/8/10 by Shirakawa]

Ok, thanks. I may have found one a touch closer, but can't bring that up no matter what channel I try. Maybe that's one like you were talking about, and considering it's part of the Asian Disaster Preparedness Center- the very first network in the "add network" dialog box- it may well be auto activated.

You catch any of these 4+ aftershocks in GEE?

Also, I was reading somewhere and apparently readings can get into the centimeters per second on huge quakes with the station very close. I think I saw some seismograms of the great 9.5 Chile quake in 1960 that were measured in cm/sec. USGS calls it the largest earthquake in the world:

Chile
1960 May 22 19:11:14 UTC
Magnitude 9.5

The Largest Earthquake in the World

Chile
Approximately 1,655 killed, 3,000 injured, 2,000,000 homeless, and $550 million damage in southern Chile; tsunami caused 61 deaths, $75 million damage in Hawaii; 138 deaths and $50 million damage in Japan; 32 dead and missing in the Philippines; and $500,000 damage to the west coast of the United States.

Severe damage from shaking occurred in the Valdivia-Puerto Montt area. Most of the casualties and much of the damage was because of large tsunamis which caused damage along the coast of Chile from Lebu to Puerto Aisen and in many areas of the Pacific Ocean. Puerto Saavedra was completely destroyed by waves which reached heights of 11.5 m (38 ft) and carried remains of houses inland as much as 3 km (2 mi). Wave heights of 8 m (26 ft) caused much damage at Corral.

Tsunamis caused 61 deaths and severe damage in Hawaii, mostly at Hilo, where the runup height reached 10.6 m (35 ft). Waves as high as 5.5 m (18 ft) struck northern Honshu about 1 day after the quake, where it destroyed more than 1600 homes and left 185 people dead or missing. Another 32 people were dead or missing in the Philippines after the tsunami hit those islands. Damage also occurred on Easter Island, in the Samoa Islands and in California. One to 1.5 m (3-5 ft) of subsidence occurred along the Chilean coast from the south end of the Arauco Peninsula to Quellon on Chiloe Island. As much of 3 m (10 ft) of uplift occurred on Isla Guafo. Many landslides occurred in the Chilean Lake District from Lago Villarica to Lago Todos los Santos.

On May 24, Volcan Puyehue erupted, sending ash and steam as high as 6,000 m. The eruption continued for several weeks.

This quake was preceded by 4 foreshocks bigger than magnitude 7.0, including a magnitude 7.9 on May 21 that caused severe damage in the Concepcion area. Many aftershocks occurred, with 5 of magnitude 7.0 or greater through Nov 1.

This is the largest earthquake of the 20th Century. The rupture zone is estimated to be about 1000 km long, from Lebu to Puerto Aisen.

Note that the tsunami deaths from outside Chile are included in the 1,655 total. This is still considerably fewer than some estimates which were as high as 5,700. However, Rothe and others state that the initial reports were greatly overestimated. The death toll for this huge earthquake was less than it might have been because it it occurred in the middle of the afternoon, many of the structures had been built to be earthquake-resistant and the series of strong foreshocks had made the population wary. [ 8ae,312,40,307A,327,305A,322,339,303A,92]

Damage in Valdivia
Valdivia suffered catastrophic damage because of its proximity to the epicenter of the massive quake.

earthquake.usgs.gov...

Man oh man, that sucka would have probably brought down the whole GEE network and caused my puter to fry!

For some reason I have been having strange gut feelings about a new possible huge quake in Chile, and possibly right along the same rupture points. So I have been monitoring it now for weeks in GEE. That point seems overdue for something big, but that may not coincide with the latest tectonics theories. I dunno, mysterious subject trying to predict quakes.

I don't know if you have seen, but there was apparently some kind breakthrough in earthquake predicting technology back in 2004, in a paper submitted by seismologist Vladmir Keilis-Borok to Physics of the Earth and Planetary Interiors, an international geophysics journal.

www.wired.com...

Predicting the Next Big One
Amit Asaravala Email 01.09.04

Seismologists may soon have the ability to predict earthquakes several months in advance, say a team of researchers at the University of California at Los Angeles.

The group announced Tuesday that it had used a newly developed technique to closely forecast major earthquakes in California and Japan last year, including the magnitude 6.5 tremor that struck Paso Robles, California, in December, and the magnitude 8.3 quake near Hokkaido, Japan, in September.

The team has submitted a paper outlining the technique to Physics of the Earth and Planetary Interiors, an international geophysics journal.

Seismologist Vladmir Keilis-Borok, who is the lead researcher on the project, called the advancement a "major breakthrough."

"Short-term prediction was considered impossible by many," said Keilis-Borok. "We have built on the work of scientists from all over the world to show that it can be done."

The team's new method differs from existing techniques in that it takes into account the small "chains" of tremors that often occur before a major earthquake.

When a long chain of related earthquakes is discovered in a region, the team analyzes the area's history, in search of various seismic patterns. If other patterns are discovered, the group announces a nine-month forecast.

Although the new method does not yet allow seismologists to pinpoint the exact date and time of future earthquakes, the UCLA researchers say it lets them narrow their forecasts to a range of several months.

For instance, in June 2003, the team predicted that a magnitude 6.4 quake would hit the Central California region within nine months. The 6.5 magnitude Paso Robles quake struck on Dec. 23.

In July 2003, the team made a similar prediction for the northern portion of Japan, saying that a magnitude 7 or greater earthquake would occur sometime in the next nine months. The 8.3 magnitude Hokkaido quake hit on Sept. 25.

In both cases, earthquakes of similar magnitudes had not been detected in the regions for years.

"There is very little chance of coincidence," said Keilis-Borok. "We look for chains as a way to determine short-term precursors. But we also use accepted intermediate-term methods to eliminate alarms from chains that occur by chance."

Although the group is currently researching earthquake patterns in California, Japan and the Middle East, Keilis-Borok said his team had not yet analyzed any information for the region near Bam, Iran, where a magnitude 6.6 earthquake last month killed tens of thousands of people.

Accurate short-term earthquake prediction has long been the holy grail of seismology. However, many researchers have focused their attention on other areas after a number of disappointing results over the past two decades.

I tried to track this down, but it is apparently only accessible to institutional members.

Here is a link on him:

www.ess.ucla.edu...

The area north of Anchorage, Alaska is another place I have been monitoring heavily. While there always seems to be quakes happening out in the Aleutian Islands and beyond, this area is drawing my attention for some reason as a place where another big one might strike. That and offshore west of Oregon and Washington. Where are you primarily monitoring these days? And I am always monitoring H17A and LKWY at Yellowstone, just in case. Those two stations, while continually separately active probably because of the construction, together allow for easy discernment of whether there is a quake or not- if it doesn't show up on both of them at the same time- it's probably nothing to worry about.

Also, the northeast end of the Carribean Plate has been quite active lately, and according to what I have been reading this long string of smaller quakes there could be a precursor to something bigger. So I'm watching that too!

[edit on Tue Aug 11th 2009 by TrueAmerican]