Quake activity along the San Andreas fault is picking up

Reply Mon 18 May, 2009 02:59 pm
The Northridge was in the early 90s I remember - quite a rude awakening
for all of us at 5 am.

Oh yes, I never would hang a huge painting or mirror above the bed, that's
a definite no-no.
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Reply Mon 18 May, 2009 03:04 pm
I need to keep track of this thread because I have two children living in the Los Angeles area.

My daughter told me that last night she was with some friends at Disneyland. They closed the rides for a few hours because of the quake activity.
Reply Mon 18 May, 2009 03:13 pm
I remember Northridge and another big one and I now get them mixed up. One crunched Olive View Sanitarium and my cousin's houseware, and the next one, parts of Santa Monica - I think of that one as early nineties, and of course, Santa Monica wasn't the only place. My bro in law was very involved as a building inspector at the time..
I seem to remember both of those hitting in early morning, as CJane mentioned. I remember staring up at the ceiling, wondering if the quake would ever stop... in both cases. No, I didn't just get up and stand in a doorway, either time.

Fbaezer, though, has the ultimate a2k posts on earthquake experience.

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Reply Tue 19 May, 2009 02:12 pm
As you said, it isn't so much a sense of fear, but a not-so-subconscious awareness of your surroundings at all times and having to constantly evaluate even the slightest tremors from a number of causes to decide if this is one you need to react to with safety measures (getting under a desk/doorway) or just ignore it and go on with life. The kind of geology in the area, and how high up you were in highrises determined how easily you sensed them.

When I was commuting to work, I was always aware of freeway overpasses and did my best to not ever be stuck under one in log-jammed stop-and-go rush hour traffic; especially the ones I knew had not yet been retro-fitted. When shopping, I didn't linger in aisles with a lot of heavy items or glass containers on high shelves. I didn't park near buildings with brick facades, etc.

I made a conscious effort to be aware of my surroundings and what would give me the best protection if "the big one" were to hit at that moment.

I probably am a lot more conscious of it and more preparation-oriented than most people because of my personal experience in the Loma Prieta quake, my volunteer work with city and county emergency preparedness departments, and being a safety coordinator for the branch offices of the company I worked for.

Reply Tue 19 May, 2009 05:16 pm
Well with my fear of storms, it was genuine, irrational, and uncontrollable fear. Now I have a healthy respect for those storms and am conscious of not exposing myself unnecessarily to lightning or taking really dumb risks, but they no longer frighten me and I thoroughly enjoy them.

Daughter, a quite savvy professional woman fearless in most things--this kid rock climbs, jumps out of airplanes and stuff like that--was fairly near the epicenter of the Loma Prieta quake and it shook a real sense of mortality into her. And most times I think daughter is much like you--conscious and takes precautions, but does not spend every waking moment thinking about it or living in dread.

Still, she recounts a time I think a year or two ago she and her husband were in their kitchen when they had a pretty good rattler. She remember nothing from the time of feeling the quake and bolting and next being in the center of their double garage--alone. Returning to the kitchen her unconcerned husband grinned and suggested that the next time she runs from a quake, she not run to the part of the house that was under the second story. That incident did illustrate to her though that the fear is still very much with her.
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Reply Tue 19 May, 2009 09:17 pm
I've been through whammo quakes too, butryfly. We have different reactions. Eh, my dad was born in 1906 in Santa Rosa. (that's cheating as a ref, as it was after the earthquake, though not long after.)

I'm not saying your experiences or researches are wrong.

Indeed, by my observation of your sharpness.. I'd say you'd make a good structural engineer. And I know some structural engineers.

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Reply Fri 22 May, 2009 01:44 pm

2009 May 22 00:24:22 UTC

Earthquake Details
Magnitude 5.5
Date-Time Friday, May 22, 2009 at 00:24:22 UTC
Thursday, May 21, 2009 at 07:24:22 PM at epicenter
Time of Earthquake in other Time Zones

Location 13.913°N, 90.730°W
Depth 75.7 km (47.0 miles) set by location program
Distances 85 km (50 miles) SSW of GUATEMALA CITY, Guatemala
130 km (80 miles) W of Santa Ana, El Salvador
130 km (80 miles) SE of Quezaltenango, Guatemala
1080 km (670 miles) ESE of MEXICO CITY, D.F., Mexico


Magnitude 5.7 - PUEBLA, MEXICO
2009 May 22 19:24:23 UTC

Earthquake Details
Magnitude 5.7
Date-Time Friday, May 22, 2009 at 19:24:23 UTC
Friday, May 22, 2009 at 02:24:23 PM at epicenter

Location 18.511°N, 98.238°W
Depth 97.3 km (60.5 miles)

Distances 27 km (17 miles) ESE (114°) from Izúcar, Puebla, Mexico
38 km (24 miles) E (91°) from Atencingo, Puebla, Mexico
40 km (25 miles) NNW (330°) from Acatlán, Puebla, Mexico
60 km (37 miles) S (184°) from Puebla, Puebla, Mexico
140 km (87 miles) SE (136°) from MEXICO CITY, D.F., Mexico

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Reply Tue 26 May, 2009 03:26 pm
Now this is an interesting bit of activity. Activity in the nearby Geysers area is also continuing at an unusually frequent rate.

Preliminary Earthquake Report
Magnitude2.9 Mcd
Date-Time23 May 2009 23:01:06 UTC
23 May 2009 16:01:06 near epicenter
23 May 2009 15:01:06 standard time in your timezone

Location40.461N 121.487W
Depth3 km
Distances14 km (8 miles) NNE (30 degrees) of Mineral, CA
17 km (11 miles) ESE (112 degrees) of Viola, CA
28 km (17 miles) NW (310 degrees) of Chester, CA
71 km (44 miles) W (274 degrees) of Susanville, CA
212 km (132 miles) N (360 degrees) of Sacramento, CA

Location UncertaintyHorizontal: 0.6 km; Vertical 0.4 km
ParametersNph = 8; Dmin = 2.0 km; Rmss = 0.04 seconds; Gp = 133°
M-type = Mcd; Version = 3


Lassen Peak has the distinction of being the only volcano in the Cascades other than Mount St. Helens to erupt during the 20th century. On May 22, 1915, an explosive eruption at Lassen Peak devastated nearby areas and rained volcanic ash as far away as 200 miles (320 km) to the east.[5] This explosion was the most powerful in a 1914"17 series of eruptions that were the last to occur in the Cascades before the 1980 eruption of Mount St. Helens in Washington. Lassen Volcanic National Park was created in Shasta County, California to preserve the devastated area and nearby volcanic geothermal features.

Unlike most lava domes, Lassen is topped by craters. A series of these craters exist around Lassen's summit, although two are now covered by solidified lava and sulfur deposits. Lassen is the largest of a group of more than 30 volcanoes that have erupted over the past 300,000 years in the Lassen Volcanic Center.

Lassen is the southernmost in the chain of 18 large volcanic peaks that run from southwestern British Columbia to northern California. The peaks formed in the past 35 million years as the Juan De Fuca plate and the tiny Gorda plate to its south have been pulled under the overriding North American plate. As the oceanic crust in the Juan de Fuca plate melts under the pressure, it creates pools of lava that drive up the Cascade Range and power periodic eruptions.
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Reply Thu 28 May, 2009 08:45 am

Earthquake Details
Magnitude 7.1
Date-Time Thursday, May 28, 2009 at 08:24:45 UTC
Thursday, May 28, 2009 at 03:24:45 AM at epicenter
Time of Earthquake in other Time Zones

Location 16.783°N, 86.166°W
Depth 10 km (6.2 miles) set by location program
Distances 130 km (80 miles) NNE of La Ceiba, Honduras
225 km (140 miles) N of Juticalpa, Honduras
320 km (200 miles) NNE of TEGUCIGALPA, Honduras
1170 km (730 miles) SSW of Miami, Florida

7.1 earthquake topples homes in Honduras, Belize
By FREDDY CUEVAS " 3 hours ago

TEGUCIGALPA, Honduras (AP) " A strong earthquake killed at least one man early Thursday as it collapsed homes in Honduras and Belize and sent people running into the streets in their pajamas as far away as Guatemala City.

The magnitude-7.1 quake struck at 3:24 a.m. (0824 GMT) at the relatively shallow depth of 6 miles (10 kilometers), according to the U.S. Geological Survey in Golden, Colorado. The epicenter was 80 miles (130 kilometers) northeast of La Ceiba, Honduras.

"People were running for the door," said Alfredo Cedeno, an employee at the Gran Hotel Paris in La Ceiba. "You could really feel it and you could see it " the water came out of the pool."

A man died after his house collapsed in Pineda de la Lima, 120 miles (200 kilometers) north of the capital, Tegicugalpa, according to Carlos Gonzalez, deputy director of Honduras' Permanent Emergency Commission. A neighbor's house also collapsed, he said.

"Dozens of workers have been evacuated from factories in San Pedro Sula (in northern Honduras) because the buildings have cracks," he said. "There are cracks in the roads in several cities."

Juan Sevilla, a spokesman for Honduras' firefighters, said wooden homes collapsed in Puerto Cortes, 120 miles (200 kilometers) north of Tegucigalpa, as did a stadium wall in Comayagua, 60 miles (100 kilometers) north of the capital.

Osman Hernandez, a spokesman for the mayor of El Progreso, told Radio Satelite there was "serious damage" to Democracy Bridge, a 1957 span across Honduras' biggest river, the Ulua. He did not provide details of the damage.

Tegucigalpa Mayor Ricardo Alvarez appealed for calm as officials reported electricity, telephones and Internet connections were cut across a large part of Honduras.

"It was an earthquake of great proportions that was felt in almost the entire country," said Ana Maria Rivera, spokeswoman for the emergency commission.

In Belize, people rushed from their homes as glasses and framed pictures crashed off of shelves. At least five wooden houses on stilts collapsed in three towns and a water tower toppled in the town of Independence, local officials said. Electricity was out all the way to the Mexican border.

"I urge you not to panic, but to remain calm," National Emergency Minister Melvin Hulse said on the radio. "Your government is monitoring the situation and will be keeping you informed."

A tsunami watch was discontinued for Honduras, Belize and Guatemala.

Raul Gonzalez, a receptionist at the Gran Hotel Sula in San Pedro Sula, said guests ran into the streets in their pajamas.

"I ran out of the building and kept going for about a block before I looked back and everything had calmed," he said. "It was really strong. I have never felt anything like that."

He said the hotel did not suffer damage.

A two-story warehouse caught fire in San Pedro Sula but no injuries were reported, according to firefighter Lt. Col. Daniel Flores.

People ran into the streets as far away as Guatemala City, but firefighter Byron Juarez said a survey of firefighting offices throughout Guatemala revealed no reports of major damage.

The quake occurred in a region where the North American and Caribean plates come together, according to Gonzalo Cruz, head of geophysics at Honduras' National Autonomous University.

The USGS said a magnitude-4.8 aftershock struck off Honduras about three hours after the quake.

Reply Thu 28 May, 2009 09:45 am
0 Replies
Reply Thu 28 May, 2009 11:04 pm
3 quakes in this area, starting at 4.9, 5.0 and this latest one of 5.1.


2009 May 29 01:04:38 UTC

Earthquake Details
Magnitude 5.1
Date-Time Friday, May 29, 2009 at 01:04:38 UTC
Thursday, May 28, 2009 at 06:04:38 PM at epicenter
Time of Earthquake in other Time Zones

Location 18.345°N, 106.666°W
Depth 10 km (6.2 miles) set by location program
Distances 260 km (160 miles) WSW of Manzanillo, Colima, Mexico
290 km (180 miles) WSW of Autlan, Jalisco, Mexico
290 km (180 miles) SSW of Puerto Vallarta, Jalisco, Mexico
800 km (495 miles) W of MEXICO CITY, D.F., Mexico

Reply Wed 3 Jun, 2009 04:24 pm
Several quakes greater than 3.0 in the Pacific Rim today.

Earthquake Details
Magnitude 5.7
Date-Time Wednesday, June 03, 2009 at 21:37:34 UTC
Wednesday, June 03, 2009 at 02:37:34 PM at epicenter

Location 19.171°N, 109.311°W
Depth 10 km (6.2 miles) set by location program
Distances 180 km (110 miles) ENE of Socorro Island, Mexico
410 km (255 miles) S of Cabo San Lucas, Baja Calif. Sur, Mexico
455 km (280 miles) WSW of Puerto Vallarta, Jalisco, Mexico
1065 km (660 miles) W of MEXICO CITY, D.F., Mexico

One in Utah today also:

Earthquake Details
Magnitude 4.0
Date-Time Wednesday, June 03, 2009 at 21:47:02 UTC
Wednesday, June 03, 2009 at 03:47:02 PM at epicenter

Location 41.805°N, 112.211°W
Depth 1.6 km (~1.0 mile)
Region UTAH
Distances 6 km (4 miles) W (269°) from Riverside, UT
8 km (5 miles) W (265°) from Fielding, UT
9 km (6 miles) NNW (333°) from Garland, UT
120 km (74 miles) NNW (347°) from Salt Lake City, UT

And our most watched location with the frequent tremors:

Earthquake Details
Magnitude 3.0
Date-Time Wednesday, June 03, 2009 at 21:00:41 UTC
Wednesday, June 03, 2009 at 02:00:41 PM at epicenter

Location 38.830°N, 122.755°W
Depth 0.5 km (~0.3 mile)
Distances 3 km (2 miles) WSW (258°) from Cobb, CA
6 km (4 miles) NE (52°) from The Geysers, CA
8 km (5 miles) NW (318°) from Anderson Springs, CA
43 km (26 miles) N (354°) from Santa Rosa, CA
116 km (72 miles) WNW (286°) from Sacramento, CA

There were also a couple greater than 5.0 between Antarctica and Australia.
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Reply Tue 9 Jun, 2009 09:56 am
Many moderate earthquakes in California over the weekend. Activity is also picking up on the Calavaras and Hayward faults. With all the movement on the San Andreas, it seems to be a contest to see which of the other two faults will be nudged to the breaking point to relieve some of the stress.

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Reply Thu 9 Jul, 2009 06:34 pm
Posting this just in case it should become significant:

Mysterious tremors detected on San Andreas Fault
Jul 9 02:01 PM US/Eastern
AP Science Writer

LOS ANGELES (AP) - Scientists have detected a spike in underground rumblings on a section of California's San Andreas Fault that produced a magnitude-7.8 earthquake in 1857.

What these mysterious vibrations say about future earthquakes is far from certain. But some think the deep tremors suggest underground stress may be building up faster than expected and may indicate an increased risk of a major temblor.

Researchers at the University of California, Berkeley, monitored seismic activity on the fault's central section between July 2001 and February 2009 and recorded more than 2,000 tremors. The tremors lasted mere minutes to nearly half an hour.

Unlike earthquakes, tremors occur deeper below the surface and the shaking lasts longer.

During the study period, two strong earthquakes hit"a magnitude-6.5 in 2003 and a magnitude-6.0 a year later. Scientists noticed the frequency of the tremors doubled after the 2003 quake and jumped six-fold after 2004.

Tremor episodes persist today. Though the frequency of tremors have declined since 2004, scientists are still concerned because they are still at a level that is twice as high as before the 2003 quake.

The team also recorded unusually strong rumblings days before the 2004 temblor.

Results of the research appear in Friday's issue of the journal Science. The work was funded by the U.S. Geological Survey and National Science Foundation.

"The fact that the tremors haven't gone down means the time to the next earthquake may come sooner," said Berkeley seismologist and lead researcher Robert Nadeau.

Nadeau first discovered tremors deep in the San Andreas Fault in 2005. Before that, the phenomenon was thought only to occur in Earth's subduction zones, where one tectonic plate dives beneath another.

USGS seismologist Susan Hough found the latest observations intriguing, but said it's too soon to know what they mean.

"We don't have enough data to know what the fault is doing in the long term," said Hough, who had no part in the research.
Reply Thu 9 Jul, 2009 06:43 pm
Could be harmonic tremors, that could be bad news and it also could merely mean that energy is being redistributed along several pathways.

Harmonics can keep going for days and then go quiet before a major strain.
Reply Thu 9 Jul, 2009 07:36 pm

Preliminary Earthquake ReportMagnitude5.1 Mb
Date-Time10 Jul 2009 00:31:27 UTC
9 Jul 2009 15:31:27 near epicenter
9 Jul 2009 16:31:27 standard time in your timezone

44.550N 129.827W
26 km
455 km (283 miles) W (275 degrees) of Yachats, OR
457 km (284 miles) W (268 degrees) of Depoe Bay, OR
457 km (284 miles) W (271 degrees) of Newport, OR
537 km (334 miles) W (278 degrees) of Eugene, OR
575 km (357 miles) W (262 degrees) of Portland, OR
Reply Thu 9 Jul, 2009 07:44 pm
Interesting article about the volcanos in the Cascade mountain chain:



The Cascades volcanic arc, running from Vancouver in British Columbia down through Washington and Oregon and into northern California, was formed by the convergence of three tectonic plates with the North American plate and their subduction beneath it. As the plates collided and ground against one another, turning rock to molten lava, massive areas of land on the American west coast were wedged upwards, creating spectacular ridges and mountain ranges with about 4,000 volcanic vents, including 18 major volcanoes.

The ongoing subduction beneath the North American plate also accounts for the frequent earthquakes in the region. Of the 10 most dangerous volcanoes in the US, seven are in the Cascades (nine are in the top 12). The region accommodates a population of 10m, all of whom can conceivably be affected by volcanic activity.

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Reply Thu 9 Jul, 2009 10:28 pm
farmerman wrote:

Could be harmonic tremors, that could be bad news and it also could merely mean that energy is being redistributed along several pathways.

Harmonics can keep going for days and then go quiet before a major strain.

But the way this article describes these tremors, they are deep. Aren't harmonic tremors more shallow?
Reply Fri 10 Jul, 2009 05:29 am
harmonics just indicate a continuing energy source behind the seismic activity. They can be deep or shallow but usually are more shallow in eruptive areas.
     http://upload.wikimedia.org/wikipedia/commons/f/f7/Four-types-seismograms.gif                             HERES AN EXAMPLE OF ENERGY PLOTS
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Reply Fri 10 Jul, 2009 09:17 am

Friday, July 10, 2009


Hundreds Injured In Earthquake

A magnitude-6.0 earthquake rocked southwestern China on Thursday evening, injuring at least 336 people and collapsing 10,000 houses, state news media said.

The temblor, centered in Yunnan province's Yao'an county, damaged an additional 30,000 homes, the New China News Agency said.

Thirty people suffered severe injuries, the news service reported.

Yunnan is a quake-prone, mountainous region bordering Sichuan province, where a magnitude-7.9 quake last year left almost 90,000 people dead or missing.
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