Quake activity along the San Andreas fault is picking up

I wonder if it is the collapsing of all the underground natural gas and oil pockets as we've consumed them in that area. Smaller versions of that have occurred in the petro areas in California for years.

Heck I dunno enough about it to even speculate.

But wouldn't 'sink holes' even underground on a large scale produce a different kind of seismic reading than an earthquake? That seems reasonable to me, but I honestly don't know.

I have never heard of subsidence after extracting oil & gas. Coal, of course.

Years ago I read a pretty good one of those end-of-the-world-type novels--I think the title was Dallas Down . The gist was that so much water had been pumped out of a huge aquifer underneath Dallas that the entire area was in danger of collapsing into a giant sinkhold destroying the entire city.

They remedied the situation by diverting the Rio Grande and channeling it into the aquifer to refill it. (Mexico didn't appreciate it.) As I recall there was some kind of 'scientific commentary' that the story was fiction but the possibility that something like that could happen was not.

I don't know if the same 'science' would apply to say pumping out the Permian Basin or whatever, but it is an interesting theory.

We could certainly be in danger of draining the Oglalla Aquafier. Guess who lives on top of it, and how your golf courses stay so green.

4.0 Ml - CENTRAL CALIFORNIA
Preliminary Earthquake Report Magnitude 4.0 Ml
Date-Time

* 30 Aug 2009 19:21:22 UTC
* 30 Aug 2009 12:21:22 near epicenter
* 30 Aug 2009 11:21:22 standard time in your timezone

Location 37.951N 118.621W
Depth 6 km
Distances

* 41 km (25 miles) SSW (192 degrees) of Qualeys Camp, NV
* 44 km (27 miles) E (91 degrees) of Lee Vining, CA
* 44 km (27 miles) N (7 degrees) of Toms Place, CA
* 47 km (29 miles) NE (42 degrees) of Mammoth Lakes, CA
* 258 km (160 miles) ESE (104 degrees) of Sacramento, CA

Two small earthquakes strike near Mt. Diablo

Bay City News Service
Posted: 09/13/2009 05:38:24 PM PDT
Updated: 09/13/2009 05:40:42 PM PDT

Two small earthquakes struck within minutes of each other in the East Bay near Mount Diablo this afternoon, according to the U.S. Geological Survey.

According to the USGS, a 3.2 magnitude earthquake struck shortly before 3:55 p.m. in an area seven miles south-southwest of Brentwood and eight miles east-northeast of Blackhawk.

About two minutes later, a 2.8 magnitude earthquake struck in the same location, according to the USGS.

The 3.2 magnitude earthquake had a depth of 7.2 miles, while the 2.8 magnitude had a depth of 6.6 miles, according to the USGS.

A 2.9 magnitude earthquake also struck in the North Bay this afternoon. According to the USGS, that quake struck shortly after 3:30 p.m. and had a depth of 1.3 miles.

It was centered five miles east-southeast of The Geysers and 16 miles east of Cloverdale, according to the USGS.

Is Mt. Diablo a volcano by any chance? Whatcha doing up so late?

No volcano, its a remnant ocean basin thats been squoze by tectonics. Mt Diablo is one of those precious areas that humans have encroached upon and left as a standout "Artificial Monadnok" where the tacky housing developments crawl right up the side of the mountain at its base and stop abruptly where the Park starts. Crying SHame cause its a standout beautiful place in the BAy ARea. People dont give a **** about our natural heritage when there a way to **** up an area for commercial gain.

Heres the geology of the Park written in non jargon.

The entire rim is active right now.

Interesting FM. Thanks for that.

I have been watching the usgs earthquake maps and have noticed quite a large increase in the number of quakes in Calif. Last week alone over 450 in one week. Usually it's about 320 per week. Gonna keep eyeing it really closely.

Welcome to A2K Kathy.

Magnitude 8.0 - SAMOA ISLANDS REGION
2009 September 29 17:48:11 UTC

Earthquake Details
Magnitude 8.0
Date-Time

* Tuesday, September 29, 2009 at 17:48:11 UTC
* Tuesday, September 29, 2009 at 06:48:11 AM at epicenter
* Time of Earthquake in other Time Zones

Location 15.558°S, 172.073°W
Depth 18 km (11.2 miles) set by location program
Region SAMOA ISLANDS REGION
Distances 185 km (115 miles) ENE of Hihifo, Tonga
195 km (125 miles) S of APIA, Samoa
705 km (435 miles) NNE of NUKU'ALOFA, Tonga
2700 km (1670 miles) NNE of Auckland, New Zealand
Location Uncertainty horizontal +/- 6.6 km (4.1 miles); depth fixed by location program

Earthquake Summary

The broad-scale tectonics of the Tonga region are dominated by the relative convergence of the Pacific and Australia plates, with the Pacific plate subducting westward beneath the Australia plate at the Tonga trench. At the latitude of the earthquake of September 29, 2009, the Pacific plate moves westward with respect to the interior of the Australia plate at a velocity of about 86 mm/year. The earthquake occurred near the northern end of a 3,000 km long segment of the Pacific/Australia plate boundary that trends north-northeast.; farther north of the earthquake’s source region, the plate boundary trends northwest and then west. The eastern edge of the broad Australia plate may be viewed as a collection of small plates or microplates that move with respect to each other and with respect to the Pacific plate and the Australia plate interior.

On the basis of currently available location and fault mechanism information, we infer that the September 29 earthquake occurred as a normal fault rupture on or near the outer rise of the subducting Pacific plate.

The broad-scale Australia/Pacific plate boundary is one of the most active earthquake regions in the world. Earthquakes occur on the thrust-fault boundary between the Australia and Pacific plates, within the Pacific plate on both sides of the trench, and within and on the boundaries of the small plates that compose the eastern edge of the overall Australia plate.

---------------------------------------------
http://www.npr.org/blogs/thetwo-way/2009/09/83_magnitude_earthquake_causes.html

8.3 Magnitude Pacific Earthquake Causes Deaths, Destruction: Reports

4:24 pm

September 29, 2009

By Frank James

There are reports of some deaths and destruction because of the 8.3 magnitude earthquake that occurred under the Pacific Ocean about 125 miles southwest of American Samoa.

Reuters is reporting that there were some deaths:

SAN FRANCISCO, Sept 29 (Reuters) - A tsunami following an earthquake in the Pacific Ocean off has caused some deaths in American Samoa , but there is no word of how many died, an official for the U.S. National Park Service said on Tuesday.

Holly Bundock, spokeswoman for the National Park Service's Pacific West Region in Oakland, California, quoted Mike Reynolds, superintendent of the National Park of American Samoa, as saying there had been some deaths.

The Associated Press isn't yet reporting any deaths. But it does report that at least one village was completely destroyed:

PAGO PAGO, American Samoa (AP) - A powerful 8.3-magnitude earthquake struck in the South Pacific between Samoa and American Samoa around dawn Tuesday, sending terrified residents fleeing for higher ground as a tsunami swept ashore, flattening at least one village. There were no immediate reports of fatalities.

http://www.reuters.com/article/marketsNews/idUSSYA00612320090929

Pacific tsunami kills people in W.Samoa - police
Tue Sep 29, 2009 4:17pm EDT

WELLINGTON, Sept 30 (Reuters) - A South Pacific tsunami killed an unknown number of people in Western Samoa on Wednesday, a local police spokeswoman said, as the island nation's people fled to higher ground after a big sub-sea quake.

"The tsunami has struck some parts of the country," a local police spokeswoman said by phone. Asked if there had been any deaths, she added: "Yes" and then hung up.

The epicenter of the 8.0 magnitude quake was located 120 miles (190 km) southwest of American Samoa, which lies near Western Samoa, the U.S. Geological Survey said. (Reporting by Adrian Bathgate, editing by Mark Bendeich)


http://www.marketwatch.com/story/tsunami-warning-in-effect-for-new-zealand-2009-09-29

Sept. 29, 2009, 3:02 p.m. EDT · Recommend · Post:
Tsunami warning in effect for New Zealand
Story Comments Screener (3)
Alert Email Print Share By Wallace Witkowski

SAN FRANCISCO (MarketWatch) -- The National Weather Service's Pacific Tsunami Warning Center issued a tsunami warning for New Zealand and other Pacific islands following a 7.9 magnitude earthquake. The quake occured at 1:48 p.m. Eastern time at a depth of 21.7 miles and was centered 125 miles south-southwest of Apia, Samoa, and 1,670 miles north-northeast of Auckland, New Zealand, according to the U.S. Geological Survey. A tsunami watch, less serious than a warning, was issued for Hawaii, with any possible effect occuring at 1 p.m. local time, or 8 p.m. Eastern, the PTWC said.

Hi Kathy,

Yeah, I've been watching them for about 30 years, more intensely after the Loma Prieta quake. About 2 years ago the activity picked up again after quieting down after the big quakes of '79 and '80. In the last 8 months the number and intensity has been slowly increasing. It is still unknown where the big one is going to hit. In Northern California it could go either way, the Hayward fault or the San Andreas fault again. In Southern California, it looks like most of the activity is centered in the Palm Springs/Yucca Valley area.

Major deadly quakes in Indonesia again, big aftershocks in the mid Pacific near Samoa, and heavier activity along the San Andreas. According to an earthquake expert on TV this morning, this could all be related.

5.1 Ml - CENTRAL CALIFORNIA
Preliminary Earthquake Report Magnitude 5.1 Ml
Date-Time

* 1 Oct 2009 10:01:23 UTC
* 1 Oct 2009 03:01:23 near epicenter
* 1 Oct 2009 02:01:23 standard time in your timezone

Location 36.380N 117.861W
Depth 0 km
Distances

* 12 km (8 miles) S (175 degrees) of Keeler, CA
* 16 km (10 miles) ENE (65 degrees) of Cartago, CA
* 18 km (11 miles) NE (43 degrees) of Olancha, CA
* 30 km (18 miles) SE (141 degrees) of Lone Pine, CA
* 237 km (148 miles) W (276 degrees) of Las Vegas, NV

http://latimesblogs.latimes.com/lanow/2009/10/earthquake-swarm-hits-californias-eastern-sierra-region-including-51-temblor.html

Earthquake swarm hits California's Eastern Sierra, including 5.1 Inyo County temblor [updated]
October 1, 2009 | 7:18 am

Inyo County was struck by a swarm of earthquakes this morning, including a 5.1 temblor around 3 a.m.

According to the U.S. Geological Survey, there have been more than 30 temblors centered about seven miles from the tiny town of Keeler, 11 miles from Lone Pine and 148 miles from Las Vegas.

[Correction: An earlier version of this post attributed information about the quake location to the National Weather Service. That information was provided by the U.S. Geological Survey]

Quake swarms have occurred before around California, notably in the Mammoth Lakes area and around the Salton Sea.

There were no immediate reports of damage or injuries.

While most temblors in the quake swarm were tiny, there were several 3.5 aftershocks to the 5.1 main quake.

Interesting observations... What do you think about them, Farmerman?

Geologists have always insisted that quakes in other geo-regions are unrelated to what happens locally. Sounds like they may be discovering there is a relationship after all. I've always believed there was a relationship between them. I'm happy to see the science beginning to make similar observations.


http://www.reuters.com/article/newsOne/idUSTRE58T6OC20090930

Strong earthquakes may weaken distant fault lines
Wed Sep 30, 2009 4:12pm EDT

By Julie Steenhuysen

CHICAGO (Reuters) - Powerful earthquakes may be a trigger for weakening geologic faults a half a world away, U.S. researchers said on Wednesday in a study that points to new ways to predict earthquakes.

"Earthquakes are caused when a fault fails, either because of the build-up of stress or because of a weakening of the fault," said earthquake researcher Taka'aki Taira, formerly of the Carnegie Institution in Washington and now of the University of California Berkeley.

Taira's team analyzed 20 years of seismic data from the Parkfield area of California's San Andreas fault.

They noticed areas of fluid-filled cracks along the fault appeared to shift from time to time -- often after large, far-away earthquakes, such as the 2004 Sumatra-Andaman Earthquake.

"We speculate that changes we see at Parkfield could be happening in many places in the world," Taira said in a telephone interview.

He said his team plans to gather data from other fault zones to see if they detect the same pattern of changes.

The researchers will also for changes at Parkfield to see if they can detect a significant impact from recent powerful earthquakes this week in Samoa and on Indonesia's Sumatra island.

SUBTLE CHANGES

For the study, Taira's team used motion-sensing equipment called seismometers bored into the Earth's crust to detect subtle changes in earthquake waves.

They noticed that when fluid levels changed in cracks along the fault, repeating earthquakes that occur in the fault zone got smaller, but more frequent -- a sign the fault was getting weaker.

"The total displacement of the fluids is only about 10 meters (30 feet) at a depth of about three kilometers (1.8 miles), so it takes very sensitive seismometers to detect the changes," Fenglin Niu of Rice University in Texas, who worked on the study, said in a statement.

He said that movement of the fluid in these cracks appears to lubricate the fault zone, weakening the fault.

Taira and colleagues think that by monitoring changes in fluids that fill up cracks near fault lines, they may be able to predict when faults are growing weaker, offering a way to predict earthquakes.

Changes in fault strength are much harder to measure than changes in stress, especially for faults deep in the Earth's crust, he said.

"Our result opens up exciting possibilities for monitoring seismic risk and understanding the causes of earthquakes," Taira said.

Yep, I think we're going to be witness to (hopefully not in our lifetimes) a major quake along the West Coast of North America as part of the ongoing process of continental drift. The quakes in the Sumatra and Samoa trench areas are making room for it by shoving more of one plate under the other. All the excess gasses and lava has to go somewhere. We'll also see some sleeping volcanos come back to life.

Such stuff is fascinating to me--I do pray not morbid fascination. If I had it all to do over again, I think I would look long and hard at earth sciences as my primary vocation. Even as I would never want any living creature threatened or harmed, I would very much like to be a witness to birth of or the reawakening of a great volcano, and I take intense interest in what happens during an earthquake, a major tsunami, hurricanes, tornadoes, etc.

Maybe I just have to admit that I'm more wierd than the average bear.