Northern California Earthquakes

2 moderate earthquakes along the Northern California coast

Last update: July 21, 2012 at 11:45 am by By

2 moderate earthquakes along the Northern California coast
While looking into the details about these earthquakes, we found a number of coincidences which may be realated to each other. The series started with a M4.0 earthquake at a depth of 10.1 km (6.3 miles) along the Blanco fracture zone in front of the Oregon coast. Nothing special as the stress in the part of the fault is generating regular earthquakes up to M6.0.
1 hour and 18 minutes later a more powerful M5.1 earthquake occurred along the Gorda ridge fault (separating plates), but this time more to the south in the Californian sector. The depth was set to 10 km or 6.2 miles but this is the usual depth which is set if the data are not accurate enough.
Finally (at least up to now) a M5.2 earthquake  occurred at a depth of 0.6 km approx. in the same sector than the earlier M5.1 earthquake. The depth of the last M5.2 earthquake (even poorly constrained) is attracting our attention.  We do not sea anything special on the sea floor except some stress scars and ridges (red lines on the three maps below).
There is certainly no proved relation in between the Oregon and California events, but if ER detects patterns, we like to share them with our readers. The separating plates (spreading center) have been related in the past to a number of volcanic ridge eruptions (like they often are occurring in the spreading ridges of the Oceans). Evidence of such an eruption may be noticed by a coloring of the surface waters. Satellite imagery will probably give us a clue later today.
Only few people at the Eureka coast have reported the shaking at USGS. All of them reported a weak to very weak shaking.

California coast M5.2 earthquake - Image courtesy USGS
California coast M5.1 earthquake - Image courtesy USGS
Oregon coast M4.0 earthquake - Image courtesy USGS

 

Sea bed at the epicenter area of the 2 California earthquakes
Detailes plate tectonics along te California and Oregon coasts - Image courtesy Wikipedia
Seismogram at Mount Pierce, relatively close to the epicenters of both CA quakes
from:    http://earthquake-report.com/2012/07/20/major-earthquakes-list-july-21-2012/

 

Fireball in the Sierra Nevadas

SIERRA FIREBALL DECODED: On Sunday morning, April 22nd, just as the Lyrid meteor shower was dying down, a spectacular fireball exploded over California’s Sierra Nevada mountain range. The loud explosion rattled homes from central California to Reno, Nevada, and beyond. According to Bill Cooke, head of NASA’s Meteoroid Envronment Office, the source of the blast was a meteoroid about the size of a minivan.

“Elizabeth Silber at Western University has searched for infrasound signals from the explosion,” says Cooke. “Infrasound is very low frequency sound which can travel great distances. There were strong signals at 2 stations, enabling a triangulation of the energy source at 37.6N, 120.5W. This is marked by a yellow flag in the map below.”

“The energy is estimated at a whopping 3.8 kilotons of TNT, so this was a big event,” he continues. “I am not saying there was a 3.8 kiloton explosion on the ground in California. I am saying that the meteor possessed this amount of energy before it broke apart in the atmosphere. [The map] shows the location of the atmospheric breakup, not impact with the ground.”

“The fact that sonic booms were heard indicates that this meteor penetrated very low in atmosphere, which implies a speed less than 15 km/s (33,500 mph). Assuming this value for the speed, I get a mass for the meteor of around 70 metric tons. Hazarding a further guess at the density of 3 grams per cubic centimeter (solid rock), I calculate a size of about 3-4 meters, or about the size of a minivan.”

“This meteor was probably not a Lyrid; without a trajectory, I cannot rule out a Lyrid origin, but I think it likely that it was a background or sporadic meteor.”

fr/spaceweather.com

Quake Proof Balancing Rocks

ysterious Balancing Rocks Resist Quakes’ Shakes

Andrea Mustain, OurAmazingPlanet Staff Writer
Date: 22 April 2012 Time: 02:19 PM ET

 

A Precariously Balanced Rock, or PBR.
A Precariously Balanced Rock, or PBR.
CREDIT: James Brune

SAN DIEGO — In the western San Bernardino Mountains, near the highway that links Los Angeles and Las Vegas, scientists recently discovered a geological mystery: colossal rocks perched in precarious poses right next door to the San Andreas Fault.

It’s not the rocks’ balancing act that is perplexing, said Lisa Grant Ludwig, a scientist who presented this puzzle to colleagues this week here at the annual meeting of the Seismological Society of America. It’s how the rocks have managed to stay that way with such an aggressive maker of powerful earthquakes just a few miles away.

Rocks with seemingly acrobatic balance are seen all over the world. Meteorological and geological forces wash away the material around them, leaving the giant rocks balancedlike a top. There’s even a term for them: Precariously Balanced Rocks, or PBRs for short, said Ludwig, an assistant professor at the University of California, Irvine.

“When you start to get into seismically active areas there are fewer and fewer,” Ludwig told OurAmazingPlanet. “And you don’t expect to see them right next to active faults —and you don’t, generally.”

Still standing

In fact, PBRs are used to verify earthquake hazard maps. “Quite some time ago it was recognized that wherever you see these things, it’s an indication there haven’t been a lot of really strong earthquakes because they haven’t been shaken down,” Ludwig said.

That’s what makes the San Bernardino PBRs so very strange. There are two pockets of more than a dozen of the gracefully balancing rocks, and some are only 4 miles (7 kilometers) from the fault.

Ludwig said that when a colleague brought her pictures of the rocks — and asked how they could possibly withstand the earthquakes that tear along the San Andreas Fault — she had to go see them for herself.

“I have spent most of my career documenting large earthquakes on the San Andreas Fault,” Ludwig said. “I could rock some of [the PBRs] with my hand.”

Seismic mystery

Subsequent dating research revealed that the rocks had been standing in their positions for millennia — in some cases as long as 18,000 years. “That’s a long time for something that is so close to a big fault,” Ludwig said.

It’s not clear why violent shaking has apparently spared the two small pockets near the fault where the rocks still stand. “I think it shows an area of complexity in the fault rupture,” Ludwig said, “and that is what a lot of my colleagues seem to agree on in the discussion.”

She said it’s something that researchers will be pursuing next. “We don’t have a good explanation,” she said.

from:    http://www.livescience.com/19840-mysterious-balancing-rocks.html

Earthquake — San Francisco

Moderate earthquake in the San Fransisco Bay Area (epicenter at East Richmond Heights)

Last update: March 5, 2012 at 3:47 pm by By 

Most important Earthquake Data:
Magnitude : 4.0
UTC Time : Monday, March 05, 2012 at 13:33:12 UTC
Local time at epicenter : Monday, March 05, 2012 at 05:33:12 AM at epicenter
Depth (Hypocenter) : 8.8 km  (5.5 miles)
Geo-location(s) :
2 km (1 miles) N (1°) from El Cerrito, CA
2 km (1 miles) SE (137°) from East Richmond Heights, CA
4 km (2 miles) E (96°) from Richmond, CA
7 km (4 miles) NNW (341°) from Berkeley, CA   


 

Update 14:55 UTC
– El Cerrito police reported not having received any damage or injury reports.
– An aftershock was reported near the epicenter about 30 minutes later.
– Luckily, still NO reports of damage or injuries

Update 14:41 UTC
BART trains were halted temporarily and service soon resumed.

Update 14:40 UTC
Coordinates released by the U.S. Geological Survey place the epicenter at the Mira Vista Golf and Country Club along the Hayward Fault, which runs through the East Bay hills. The Hayward Fault is considered by many seismologists to be a prime candidate for a major earthquake. The 2010 update of the report, “On Shaky Ground,” by the Association of Bay Area Governments, reported that there’s an estimated 62 percent probability of a destructive quake of magnitude 6.7 or greater in the Bay Area in the years 2003-2032.

Update 14:32 UTC

Update 14:29 UTC
– Based on the current reported shaking values, earthquake-report.com does not expect to see major damage during this earthquake. We do not exclude cracks in walls, objects falling from shelves etc.

Update 14:24 UTC
– The fault line were today’s earthquake took place is the same as the one which was responsible for a number of other quakes from the preceding months.

Update 14:10 UTC
– 27,000 people will have experienced a strong shaking (East Richmond Heights and El Cerrito)
– 276,000 people a moderate shaking (MMI V) (Kensington, Albany, El Sobrante and Richmond)

– This earthquake will probably not lead to any damage but it surely must have been scary so early in the morning

from:    http://earthquake-report.com/2012/03/05/moderate-earthquake-in-the-san-fransisco-bay-area/

Eureka, CA Area Earthquake

Strong earthquake in the greater Eureka area, California, USA – NO damage so far

Last update: February 14, 2012 at 12:16 am by By 

Image shaking map courtesy USGS

Most important Earthquake Data:
Magnitude : 5.4
UTC Time : Monday, February 13, 2012 at 21:07:02 UTC
Local time at epicenter :  Monday, February 13, 2012 at 01:07:02 PM at epicenter
Depth (Hypocenter) : 32.9 km
Geo-location(s) :
10 km (6 miles) WSW (247°) from Weitchpec, CA
28 km (17 miles) ENE (63°) from Westhaven-Moonstone, CA
29 km (18 miles) ENE (70°) from Trinidad, CA
50 km (31 miles) NE (36°) from Eureka, CA

Earthquake overview : A strong earthquake occurred near Redwood National park in California. Distance from the epicenter until Eureka approx. 50 km

Update 22:50 UTC : The Cal Fire reports that “No damage has been reported to CAL FIRE stations.” (Cal Fire = California Department of Forestry and Fire Protection).

Update 22:42 UTC :  Police is currently making assessments in the more remote locations of the direct epicenter area to find out if damage would have been inflicted (even minor).

Update 22:14 UTC :  As of 1:25 p.m. theEureka Police Department had no reports of damage. The temblor was widely felt and that the shaking lasted 30 to 45 seconds.

Update 22:04 UTC :  The area has experienced a massive M 7.3 earthquake on November 8, 1980. 16000 people have been shaken up to a IX MMI, but luckily nobody was killed.

Update 21:59 UTC :  The earthquake has been felt until Sacramento, CA and also in Southern Oregon.

Update 21:59 UTC :  The magnitude has been updated by USGS to Mw 5.6 at a depth of 32.9 km.

Update 21:51 UTC :  Eureka (26,000 people) and Arcata (17,000 people) are the most populated cities in this mainly sparsely populated area. Eureka and Arcata have experienced a light MMI IV shaking. McKinleyville has a population of 15,000 and has also experienced a light shaking.

Update 21:49 UTC :  15 people will have experienced a strong shaking, 4,000 people a moderate shaking and 102,000 people a light shaking.

Update 21:41 UTC :  The depth of the hypocenter will lead to a weak shaking in a very vast area
for more information, and updates, go to:    http://earthquake-report.com/2012/02/13/strong-earthquake-in-the-greater-eureka-area-california-usa/

Storm Targets California Monday

Major Storm to strike Southern California on Monday, bringing Severe Weather

Published on December 11, 2011 10:00 am PT
– By TWS Staff Reporter
– Edited by Staff Editor


(TheWeatherSpace.com) – TWS’ Southern California Weather Authority has issued a Severe Weather Statement for the populated zones of Southern California for Monday for severe weather to strike.

TWS Senior Meteorologist Kevin Martin issued the product this morning just after 9:30 a.m. Pacific Time. The skies are clear across Southern California and it does not even seem like a major storm is on the horizon, but there is

“This is one of those systems that goes negative tilted, which means the dynamics for widespread thunderstorms and a chance of severe weather, including tornadic activity, is possible. The best dynamics is offshore Orange County, which means areas along the Orange County coast and inland need to be aware.”

TWS SCWXA has named the system the next name on the list, Garrett. Major Pacific Storm Garrett is a category four to start, but Martin stresses the highest scale of five could be issued by tonight if trends continue.

“In addition to this, the mountains above 5,000 feet will take a beating with the system, bringing significant snowfall to those areas and thundersnow,” concluded Martin.

from:   http://www.theweatherspace.com/news/TWS-121111-major-storm-southern-california.html
.

Dangerous WInds Hit L.A.

Wind storm disrupts traffic, flights and power in Los Angeles 

A portion of a broken tree is pictured following a wind storm in Pasadena, California, December 1, 2011.  REUTERS/Mario Anzuoni

By Steve Gorman

LOS ANGELES | Thu Dec 1, 2011 4:39pm EST

(Reuters) – A powerful wind storm with gale-force gusts left much of the Los Angeles area strewn with toppled trees and downed power lines on Thursday, slowing rush-hour traffic and knocking out electricity to over 300,000 customers.

An hourlong power outage at Los Angeles International Airport forced nearly two dozen inbound commercial flights to be diverted to other airports, and flight delays lingered after electricity was restored at about 8 a.m. local time, LAX spokeswoman Nancy Castles said.

Utility crews were out in force, working to restore electricity and remove uprooted trees and fallen limbs that littered neighborhoods throughout the region, blocking streets in many places.

Authorities said at least one house in Los Angeles, and an apartment building and gas station in Pasadena were hit by fallen trees, but no one was reported hurt.

Janelle Brown, 38, said the house she and her husband moved into a week ago in Los Angeles’s Silver Lake neighborhood, narrowly escaped a direct hit from a large 100-year-old pepper tree that was uprooted in the middle of their backyard overnight.

“We woke up this morning, looked out the window, and realized it was gone,” she told Reuters, adding she and her husband never heard it fall.

“We lay in bed until 1:30 in the morning listening to the cracks and the pops and the wind rattling the windows, and then finally fell asleep,” she said.

Brown, a novelist, said some branches from the tree came to rest on top of her house, and “there’s a little bowing in the roof, but from what we can tell, we got lucky.”

Public schools in Pasadena and 11 other districts in San Gabriel Valley, northeast of Los Angeles, were closed for the day, though the Los Angeles Unified School District said it would remain open.

The Los Angeles Department of Water and Power, the nation’s largest public utility, reported nearly 129,000 of its customers were without electricity Thursday morning.

Southern California Edison, which serves areas outside the city of Los Angeles, said outages that began Wednesday night had affected more than 213,000 homes and businesses.

Winds gusting to speeds ranging from 40 to 60 miles per hour and higher were clocked throughout the Los Angeles area starting Wednesday night and through the early morning hours of Thursday, according to the National Weather Service.

Gusts of 97 miles per hour were recorded overnight at Whitaker Peak in the San Gabriel Mountains.

The winds had largely died down by daybreak, but forecasters said blustery weather was expected to return, with sustained winds ranging from 45 to 60 miles per hour and gusts of up to 85 possible through Friday.

The Weather Service said the wind storm was produced by the combination of a low-pressure system that materialized over the California-Nevada border area and a zone of surface-high pressure originating in the Great Basin.

The advent of high winds put fire departments throughout the region on alert for a high risk of wildfires.

(Editing by Cynthia Johnston)

from:    http://www.theweatherspace.com/news/TWS-120111-damaging-winds-los-angeles.html

Cold Air Heading towards California

Cold storm system to slam California Thursday, to Southern California Friday

Published on November 2, 2011 12:55 pm PT
– By TWS Senior Meteorologist
– Edited by Staff Editor


(TheWeatherSpace.com) – A cold Winter-like storm will hit California on Thursday, starting in Northern California and heading into Southern California on Friday. This will provide low elevation snowfall in Northern California.

The storm will impact Northern California’s Interstate 5 with a few inches of snow and the Sierra Nevada Range over a foot. Drivers North of Sacramento driving toward Oregon on Interstate 5 should use extra caution with those several inches expected.

There will be cold air aloft with this one, enough for thunderstorms to form from the Bay area down into Southern California. The bay area will get it early Friday morning, Southern California later in the day on Friday.

The snow level in Southern California with this storm will be around 4,000 feet, lower in convective (thunderstorm) activity. There is a very good chance the Cajon and Gorman Pass will be affected with this snowfall.

Thunderstorms are likely from San Francisco to Southern California, strong damaging winds in the mountain and desert regions likely, blizzard conditions in the mountain areas, high surf, and heavy rainfall (small hail)

from http://www.theweatherspace.com/news/TWS-110211_cold-california-winter-storm.html

Earthquake—Riverside, California

Moderate earthquake near Riverside, California, USA – NO damage or injuries

Last update: September 14, 2011 at 4:24 pm by By 

Earthquake overview :  At 7:44 a moderate shallow earthquake struck 8 km from Yucaipa and 109 km from LA downtown.

FINAL update 16:22 UTC : After screening our many sources (all Fire Department brigades and some supermarkets in the epicenter area), we are happy to report that this earthquake made NO damage, injuries or casualties

to read more, and for up dates, go to:   http://earthquake-report.com/2011/09/14/moderate-earthquake-in-greater-los-angeles-california-usa/

Power Outtages CA to Mexico

 

Major power outage hits from San Diego to New Mexico on Thursday

Published on September 8, 2011 5:10 pm PT
– By Dave Tole – Writer
– Article Editor and Approved – Warren Miller


No larger image

(TheWeatherSpace.com) — Power is out from San Diego into Arizona, and New Mexico in spots, blamed on hot conditions in the Southern California desert.

San Diego Gas and Electric spoke this evening when millions of people were affected with a power outage before 4 p.m. local time.

he spokesperson states that “power will be restored soon as other plants come online” but does not have an approximate time for it.

The internet is abuzz with possible reasons. An X-Class solar flare erupted from the Sun a couple days back which could result in a solar storm today or tomorrow.

Then you have the more realistic reason being the hot temperatures over 115 degrees overloaded the grid in the desert, causing the blackout.

“Temperatures are very hot out there in the Southern California desert,” said TWS Senior Meteorologist Kevin Martin. “Anytime you have something of that magnitude you will get power failures. It is a plausible option but not for sure.”

Others tell TheWeatherSpace.com it was traced to someone removing a piece of monitoring equipment at a power substation in Southwestern Arizona.

fr/   http://www.theweatherspace.com/news/TWS-09_08_2011_sandiegopower.html