Quake activity along the San Andreas fault is picking up

3.5 Ml - NORTHERN CALIFORNIA
Preliminary Earthquake Report Magnitude 3.5 Ml
Date-Time

* 15 Jul 2010 23:54:20 UTC
* 15 Jul 2010 16:54:20 near epicenter
* 15 Jul 2010 15:54:20 standard time in your timezone

Location 38.814N 122.814W
Depth 2 km
Distances

* 2 km (1 miles) NNW (340 degrees) of The Geysers, CA
* 8 km (5 miles) WSW (254 degrees) of Cobb, CA
* 11 km (7 miles) WNW (292 degrees) of Anderson Springs, CA
* 42 km (26 miles) NNW (347 degrees) of Santa Rosa, CA
* 120 km (75 miles) WNW (284 degrees) of Sacramento, CA

Washington D.C. had one this morning of 3.6.

Magnitude 6.7 - FOX ISLANDS, ALEUTIAN ISLANDS, ALASKA
2010 July 18 05:56:49 UTC

Earthquake Details

Magnitude 6.7
Date-Time

* Sunday, July 18, 2010 at 05:56:49 UTC
* Saturday, July 17, 2010 at 09:56:49 PM at epicenter
* Time of Earthquake in other Time Zones

Location 52.970°N, 169.504°W
Depth 35 km (21.7 miles) set by location program
Region FOX ISLANDS, ALEUTIAN ISLANDS, ALASKA
Distances 45 km (25 miles) W of Nikolski, Alaska
85 km (55 miles) ENE of Yunaska Island, Alaska
1500 km (930 miles) WSW of Anchorage, Alaska
2265 km (1400 miles) W of JUNEAU, Alaska

000
WEHW42 PHEB 180613
TIBHWX

HIZ001>003-005>009-012>014-016>021-023>026-180813-

TSUNAMI INFORMATION STATEMENT NUMBER 2
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
813 PM HST SAT JUL 17 2010

TO - CIVIL DEFENSE IN THE STATE OF HAWAII

SUBJECT - TSUNAMI INFORMATION

NOTE: ATWC DOES NOT HAVE A WARNING IN EFFECT. PREVIOUS
BULLETIN WAS IN ERROR. THERE IS NO WARNING IN EFFECT
ANYWHERE IN THE PACIFIC.

THIS STATEMENT IS FOR INFORMATION ONLY. NO ACTION REQUIRED.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

ORIGIN TIME - 0757 PM HST 17 JUL 2010
COORDINATES - 52.5 NORTH 169.5 WEST
LOCATION - FOX ISLANDS ALEUTIAN ISLANDS
MAGNITUDE - 6.7 MOMENT

EVALUATION

BASED ON ALL AVAILABLE DATA A DESTRUCTIVE PACIFIC-WIDE TSUNAMI IS
NOT EXPECTED AND THERE IS NO TSUNAMI THREAT TO HAWAII. REPEAT. A
DESTRUCTIVE PACIFIC-WIDE TSUNAMI IS NOT EXPECTED AND THERE IS NO
TSUNAMI THREAT TO HAWAII.

THIS WILL BE THE ONLY STATEMENT ISSUED FOR THIS EVENT UNLESS
ADDITIONAL DATA ARE RECEIVED.
...SP...

Magnitude 3.5 - LONG VALLEY AREA, CALIFORNIA
2010 July 18 06:16:26 UTC

Earthquake Details
Magnitude 3.5
Date-Time

* Sunday, July 18, 2010 at 06:16:26 UTC
* Saturday, July 17, 2010 at 11:16:26 PM at epicenter
* Time of Earthquake in other Time Zones

Location 37.621°N, 118.814°W
Depth 7.8 km (4.8 miles)
Region LONG VALLEY AREA, CALIFORNIA
Distances 15 km (10 miles) ESE of Mammoth Lakes, California
45 km (30 miles) NW of Bishop, California
80 km (50 miles) SSE of Bridgeport, California
260 km (160 miles) ESE of SACRAMENTO, California

There's a hole in this possible earthquake pattern

Excerpts:
As UC Davis physicist and geologist John Rundle ponders the map of recent California earthquakes, he sees visions of a doughnut even Homer J. Simpson wouldn't like.

The doughnut is formed by pinpointing the recent quakes near Eureka, Mexicali and Palm Springs.

Seismologists call the possible pattern a Mogi doughnut. It's the outgrowth of a concept, developed in Japan, which holds that earthquakes sometimes occur in a circular pattern over decades —building up to one very large quake in the doughnut hole. Rundle and his colleagues believe that the recent quakes, combined with larger seismic events including the 1989 Loma Prieta and 1994 Northridge temblors, could be precursors to a far larger rupture.

They just don't know exactly when.

The idea of predicting earthquakes remains controversial and much debated among California's many seismologists. But as technology improves and the understanding of how earthquakes distribute energy grows, experts are gingerly offering improved "forecasts," some of which have been surprisingly prescient.

For example, Southern California was hit earlier this month by a 5.4 quake that struck in the mountains about 30 miles south of Palm Springs — several weeks after seismologists at the Jet Propulsion Laboratory and elsewhere warned that pressure was building in the San Jacinto fault zone, which is where the temblor occurred.

That forecast underscores new thinking by seismologists about how earthquakes occur.

In the past, experts paid less attention to how one fault was connected to another and how one earthquake could increase the chances of a quake on another fault. But now they believe that these connections are extremely important and that this year's temblors along the Mexican border and near Palm Springs seem to support the concept.

...

The big question is whether the Mexicali quake has made a destructive temblor in the L.A. area more likely. Experts see strong evidence that there is more pressure now on the San Jacinto and nearby Elsinore fault networks to the east of Los Angeles. The Elsinore fault zone is connected to the Whittier fault, which runs through densely populated sections of the L.A. area, including the San Gabriel Valley. As a result, there's a concern that a quake on the Whittier fault might be more likely.

The Mexicali quake has also turned into a treasure trove of data for earthquake experts. It comes at a time when quake technology has advanced in major ways. Sophisticated satellite images are being used to study creeping ground movement caused by tectonic pressure in advance of an earthquake.

New GPS ground monitoring equipment is tracking how far the ground has moved after a quake, allowing scientists to calculate locations of greater seismic stress. And research in the mountains west of Bakersfield, examining the tracks of earthquakes hundreds of years ago, is showing that catastrophic earthquakes — those as large as magnitude 8 — have occurred in Southern California more frequently than previously believed.

That brings experts back to the Mogi doughnut.

The idea behind the doughnut is relatively straightforward: Earthquakes in California are basically caused by tectonic movements in which the Pacific plate slides northwest relative to the North American plate. As the plates move, stress builds up along both sides of cracks in the Earth's crust, as if a giant sheet of peanut brittle were being shoved in two directions.

Tectonic stress will first cause ruptures on the smaller faults, because they need less pressure before they break and thus produce small earthquakes. When they do rupture, the tectonic pressure gets transferred somewhere else, moving along like a crack in a windshield.

Ultimately, the stress moves closer to bigger faults that need more pressure to erupt, thus creating larger and larger earthquakes until the "Big One" happens.

"It's a matter of looking at the major earthquakes in California over the last 20, 30, 40 years," said UC Davis' Rundle. "They seem to be occurring everywhere except the major faults — the San Andreas, the Elsinore and the San Jacinto."

Those three faults would be enclosed in Southern California's doughnut hole. Northern California's doughnut hole includes the San Andreas and Hayward faults.

3.5 Ml - NORTHERN CALIFORNIA
Preliminary Earthquake Report Magnitude 3.5 Ml
Date-Time

* 18 Jul 2010 07:49:16 UTC
* 18 Jul 2010 00:49:16 near epicenter
* 17 Jul 2010 23:49:16 standard time in your timezone

Location 38.826N 122.810W
Depth 3 km
Distances

* 3 km (2 miles) N (355 degrees) of The Geysers, CA
* 8 km (5 miles) W (262 degrees) of Cobb, CA
* 12 km (7 miles) WNW (299 degrees) of Anderson Springs, CA
* 43 km (27 miles) NNW (348 degrees) of Santa Rosa, CA
* 120 km (75 miles) WNW (285 degrees) of Sacramento, CA

Interesting article, I had saved it.

Magnitude 5.1 - VANCOUVER ISLAND, CANADA REGION
2010 July 19 17:15:03 UTC

Earthquake Details

* This event has been reviewed by a seismologist.

Magnitude 5.1 (Preliminary magnitude — update expected within 15 minutes)
Date-Time

* Monday, July 19, 2010 at 17:15:03 UTC
* Monday, July 19, 2010 at 10:15:03 AM at epicenter

Location 49.730°N, 129.682°W
Depth 1 km (~0.6 mile) set by location program
Region VANCOUVER ISLAND, CANADA REGION
Distances

* 188 km (117 miles) WSW (237°) from Port Hardy, BC, Canada
* 320 km (199 miles) W (267°) from Campbell River, British Columbia, Canada
* 399 km (248 miles) WNW (294°) from Neah Bay, WA
* 476 km (296 miles) W (279°) from Vancouver, British Columbia, Canada

These quakes off the coast of BC are getting larger. The one from last week was a 4.1.

3.4 Ml - LONG VALLEY AREA, CALIFORNIA
Preliminary Earthquake Report Magnitude 3.4 Ml
Date-Time

* 18 Jul 2010 06:16:26 UTC
* 17 Jul 2010 23:16:26 near epicenter
* 17 Jul 2010 22:16:26 standard time in your timezone

Location 37.621N 118.814W
Depth 7 km
Distances

* 14 km (8 miles) WNW (299 degrees) of Toms Place, CA
* 15 km (9 miles) E (97 degrees) of Mammoth Lakes, CA
* 30 km (19 miles) NW (320 degrees) of Round Valley, CA
* 255 km (158 miles) ESE (113 degrees) of Sacramento, CA

4.2 Ml - NEVADA
Preliminary Earthquake Report Magnitude 4.2 Ml
Date-Time

* 20 Jul 2010 21:48:30 UTC
* 20 Jul 2010 14:48:30 near epicenter
* 20 Jul 2010 13:48:30 standard time in your timezone

Location 40.068N 119.623W
Depth 12 km
Distances

* 14 km (8 miles) N (353 degrees) of Sutcliffe, NV
* 14 km (9 miles) SE (135 degrees) of Zenobia, NV
* 34 km (21 miles) W (281 degrees) of Nightingale, NV
* 63 km (39 miles) NNE (16 degrees) of Reno, NV
* 231 km (144 miles) NE (43 degrees) of Sacramento, CA

There has been an unusual amount of activity around Nevada's big lakes in the recent weeks, including today's quake at Pyramid Lake.

I was reading up on the geologic history of Lake Tahoe and found it quite interesting.

http://en.wikipedia.org/wiki/Lake_Tahoe

Geology
Lake Tahoe from space

The Lake Tahoe Basin was formed by a geologic block (normal) faulting. A geologic block fault is a fracture in the Earth's crust causing blocks of land to move up or down. Uplifted blocks created the Carson Range on the east and the Sierra Nevada on the west. Down-dropped blocks (a graben) created the Lake Tahoe Basin in between.[2]

More technically, Lake Tahoe is the youngest of several extensional basins of the Walker Lane Deformation Belt that accommodates nearly 12 mm/yr of dextral shear between the Sierra Nevada Microplate and North America.[10][11] The Lake Tahoe basin is formed by a series of large down-to-the-east normal faults, including the West Tahoe—Dollar Point fault, Stateline/North Tahoe fault and the Incline Village fault.[12] These right-stepping en-echelon faults are capable of large magnitude 7 earthquakes, with the most recent M7 paleoquake (~1500 AD) occurring on the Incline Village fault with nearly 9.7 ft (3.0 m) of vertical offset.[13] The West Tahoe-Dollar Point Fault (WTDPF) appears to be the most active and potentially hazardous fault in the basin. A study in Fallen Leaf Lake, just south of Lake Tahoe, used seafloor mapping techniques to image evidence for paleoearthquakes on the WTDPF and revealed the last earthquake occurred between 4,100-4,500 years ago.[14]

Some of the highest peaks of the Lake Tahoe Basin that formed during process of Lake Tahoe creation are Freel Peak at 10,891 feet (3,320 m), Monument Peak at 10,067 feet (3,068 m), Pyramid Peak at 9,983 feet (3,043 m) (in the Desolation Wilderness), and Mount Tallac at 9,735 feet (2,967 m).[2]

Eruptions from the extinct volcano Mount Pluto formed a dam on the north side. Melting snow filled the southern and lowest part of the basin to form the ancestral Lake Tahoe. Rain and runoff added additional water.[15]

Modern Lake Tahoe was shaped and landscaped by scouring glaciers during the Ice Ages, which began a million or more years ago. Lake Tahoe is fed from 63 tributaries with the Truckee River as the only outlet.[3] The Truckee flows northeast through Reno, Nevada and into Pyramid Lake, Nevada which has no outlet.

Soils of the basin come primarily from andesitic volcanic rocks and granodiorite, with minor areas of metamorphic rock. Some of the valley bottoms and lower hill slopes are mantled with glacial moraines, or glacial outwash material derived from the parent rock. Cryopsamments, Cryumbrepts, rockland, rock outcrops and rubble and stony colluvium account for over 70% of the land area in the basin (see USA soil taxonomy). The basin soils (in the < 2 mm fraction) are generally 65-85% sand (0.05–2.0 mm).

Given the great depth of Lake Tahoe, and the locations of the normal faults within the deepest portions of the lake, modeling suggests that earthquakes on these faults can trigger tsunamis. Wave heights of these tsunamis are predicted to be on the order of 10 to 33 ft (3 to 10 m) in height, capable of traversing the lake in just a few minutes.[16] A massive collapse of the western edge of the basin that formed McKinney Bay around 50,000 years ago is thought to have generated tsunami/seiche wave with height approaching 330 ft (100 m).[17]

Welcome to Canada! In a few million years Californians will be part of Western Canada.

3.6 Ml - CENTRAL CALIFORNIA
Preliminary Earthquake Report
Magnitude 3.6 Ml
Date-Time

* 21 Jul 2010 06:54:35 UTC
* 20 Jul 2010 23:54:35 near epicenter
* 20 Jul 2010 22:54:35 standard time in your timezone

Location 36.831N 121.571W
Depth 8 km
Distances

* 3 km (2 miles) WSW (243 degrees) of San Juan Bautista, CA
* 9 km (6 miles) ENE (68 degrees) of Prunedale, CA
* 9 km (6 miles) SE (135 degrees) of Aromas, CA
* 15 km (10 miles) W (263 degrees) of Hollister, CA
* 63 km (39 miles) SSE (153 degrees) of San Jose City Hall, CA

4.0 Ml - LONG VALLEY AREA, CALIFORNIA
Preliminary Earthquake Report
Magnitude 4.0 Ml
Date-Time

* 22 Jul 2010 11:40:08 UTC
* 22 Jul 2010 04:40:08 near epicenter
* 22 Jul 2010 03:40:08 standard time in your timezone

Location 37.624N 118.815W
Depth 8 km
Distances

* 14 km (8 miles) WNW (300 degrees) of Toms Place, CA
* 15 km (9 miles) E (96 degrees) of Mammoth Lakes, CA
* 30 km (19 miles) NW (321 degrees) of Round Valley, CA
* 254 km (158 miles) ESE (113 degrees) of Sacramento, CA

3.5 Ml - OFFSHORE NORTHERN CALIFORNIA
Preliminary Earthquake Report Magnitude 3.5 Ml
Date-Time

* 23 Jul 2010 21:29:10 UTC
* 23 Jul 2010 14:29:10 near epicenter
* 23 Jul 2010 13:29:10 standard time in your timezone

Location 37.665N 122.515W
Depth 6 km
Distances

* 5 km (3 miles) NNW (331 degrees) of Pacifica, CA
* 5 km (3 miles) SW (236 degrees) of Daly City, CA
* 5 km (3 miles) WSW (254 degrees) of Colma, CA
* 15 km (9 miles) SW (215 degrees) of San Francisco City Hall, CA

Magnitude 4.6 - VANCOUVER ISLAND, CANADA REGION
2010 July 26 08:43:27 UTC

Earthquake Details

Magnitude 4.6
Date-Time

* Monday, July 26, 2010 at 08:43:27 UTC
* Monday, July 26, 2010 at 01:43:27 AM at epicenter
* Time of Earthquake in other Time Zones

Location 50.134°N, 129.845°W
Depth 19.6 km (12.2 miles) (poorly constrained)
Region VANCOUVER ISLAND, CANADA REGION
Distances 185 km (115 miles) WSW of Port Hardy, British Columbia, Canada
255 km (160 miles) SSW of Bella Bella, British Columbia, Canada
330 km (205 miles) W of Campbell River, British Columbia, Canada
510 km (315 miles) WNW of VICTORIA, British Columbia, Canada

3.3 Ml - NORTHERN CALIFORNIA
Preliminary Earthquake Report
Magnitude 3.3 Ml
Date-Time

* 27 Jul 2010 21:21:40 UTC
* 27 Jul 2010 14:21:40 near epicenter
* 27 Jul 2010 13:21:40 standard time in your timezone

Location 39.499N 123.124W
Depth 4 km
Distances

* 17 km (11 miles) NW (305 degrees) of Lake Pillsbury, CA
* 22 km (14 miles) ENE (61 degrees) of Willits, CA
* 36 km (22 miles) SSE (162 degrees) of Covelo, CA
* 40 km (25 miles) N (11 degrees) of Ukiah, CA
* 177 km (110 miles) NW (307 degrees) of Sacramento, CA

5.3 Mb - OFF COAST OF OREGON
Preliminary Earthquake Report
Magnitude 5.3 Mb
Date-Time

* 28 Jul 2010 16:12:06 UTC
* 28 Jul 2010 09:12:06 near epicenter
* 28 Jul 2010 08:12:06 standard time in your timezone

Location 43.770N 125.802W
Depth 10 km
Distances

* 129 km (80 miles) WNW (292 degrees) of Barview, OR
* 131 km (81 miles) W (275 degrees) of Winchester Bay, OR
* 133 km (82 miles) W (280 degrees) of Lakeside, OR
* 218 km (135 miles) W (263 degrees) of Eugene, OR
* 317 km (197 miles) SW (233 degrees) of Portland, OR

Quite a bit of activity today...



2.9 Mcd - CENTRAL CALIFORNIA
Preliminary Earthquake Report
Magnitude 2.9 Mcd
Date-Time

* 30 Jul 2010 10:56:51 UTC
* 30 Jul 2010 03:56:51 near epicenter
* 30 Jul 2010 02:56:51 standard time in your timezone

Location 36.441N 120.222W
Depth 6 km
Distances

* 11 km (7 miles) SE (131 degrees) of Cantua Creek, CA
* 19 km (12 miles) S (188 degrees) of San Joaquin, CA
* 23 km (14 miles) S (173 degrees) of Tranquillity, CA
* 36 km (22 miles) NNE (20 degrees) of Coalinga, CA
* 179 km (111 miles) ESE (123 degrees) of San Jose City Hall, CA

--------------------------------

3.9 Ml - NEVADA
Preliminary Earthquake Report
Magnitude 3.9 Ml
Date-Time

* 30 Jul 2010 11:13:46 UTC
* 30 Jul 2010 04:13:46 near epicenter
* 30 Jul 2010 03:13:46 standard time in your timezone

Location 38.623N 118.176W
Depth 5 km
Distances

* 13 km (8 miles) N (2 degrees) of Luning, NV
* 15 km (10 miles) SE (136 degrees) of Midway, NV
* 35 km (22 miles) SW (219 degrees) of Gabbs, NV
* 40 km (25 miles) ENE (74 degrees) of Hawthorne, NV
* 286 km (178 miles) E (87 degrees) of Sacramento, CA

------------------------------

4.4 Ml - NEVADA
Preliminary Earthquake Report
Magnitude 4.4 Ml
Date-Time

* 30 Jul 2010 11:13:46 UTC
* 30 Jul 2010 04:13:46 near epicenter
* 30 Jul 2010 03:13:46 standard time in your timezone

Location 38.620N 118.204W
Depth 2 km
Distances

* 13 km (8 miles) N (351 degrees) of Luning, NV
* 14 km (9 miles) SE (144 degrees) of Midway, NV
* 37 km (23 miles) SW (221 degrees) of Gabbs, NV
* 38 km (24 miles) ENE (74 degrees) of Hawthorne, NV
* 284 km (176 miles) E (88 degrees) of Sacramento, CA

-------------------------------
3.0 Mcd - NORTHERN CALIFORNIA
Preliminary Earthquake Report
Magnitude 3.0 Mcd
Date-Time

* 31 Jul 2010 01:31:57 UTC
* 30 Jul 2010 18:31:57 near epicenter
* 30 Jul 2010 17:31:57 standard time in your timezone

Location 39.314N 122.816W
Depth 9 km
Distances

* 16 km (10 miles) SE (131 degrees) of Lake Pillsbury, CA
* 19 km (12 miles) NNE (24 degrees) of Upper Lake, CA
* 21 km (13 miles) N (8 degrees) of Nice, CA
* 38 km (24 miles) ENE (61 degrees) of Ukiah, CA
* 144 km (89 miles) NW (306 degrees) of Sacramento, CA

----------------------


5.8 M - NEAR COAST OF NICARAGUA
Preliminary Earthquake Report
Magnitude 5.8 M
Date-Time

* 30 Jul 2010 14:41:28 UTC
* 30 Jul 2010 08:41:28 near epicenter
* 30 Jul 2010 06:41:28 standard time in your timezone

Location 11.591N 86.653W
Depth 96 km
Distances

* 68 km (42 miles) SW (214 degrees) of MANAGUA, Nicaragua
* 75 km (47 miles) S (187 degrees) of Nagarote, León, Nicaragua
* 85 km (53 miles) WSW (244 degrees) of Granada, Nicaragua