At 8:08pm, on Saturday night, two moderate earthquakes struck in the Anza-Borrego Desert. A 4.9 and 4.5 magnitude earthquake hit approximately 9 miles north northwest of Borrego Springs, California. Both earthquakes occurred just south of the Anza Gap and are related to San Jacinto Fault.
The first earthquake was a 4.9 magnitude quake which struck at 8:08pm.
The second earthquake was a 4.5 magnitude aftershock that struck at 8:09pm.
Because the earthquakes struck so close together, only 24 seconds separated the two seismic events, the USGS had trouble determining the exact magnitude, location, and whether they had one or two events recorded. Within the first hour, the magnitudes were revised multiple times and the sizes ranged from 4.4 to 4.9 in magnitude.
At the time of this posting, the official answer seems to be that two quakes occurred, a magnitude 4.9 and a 4.5.
The epicenter of both quakes were far from any major town. Anza and Borrego Springs were the closest towns to the epicenter, both small desert communities. The San Diego Union Tribune quoted a clerk at the Borrego Springs Resort as saying, "...the building’s glass shook but did not break, and the resort had no damage." No damage or injuries were expected elsewhere as well.
Despite the quake being considered small to moderate, it was widely felt strongly by many in Imperial, San Diego, Orange, and San Bernandino county areas, as well as by people in the Los Angeles city area. Additionally, felt reports were received from Tijuana, Tecate, and Mexicali, Mexico.
Some of the communities that turned in the most felt reports included Carlsbad, Ramona, La Quinta, Santee, Escondido, San Diego, Poway, Encinitas, Temecula, San Marcos, Fallbrook, Palm Desert, Murrieta, and Oceanside.
I personally felt this quake while I was at work in Carlsbad, California. I was in an office building at the time, ground floor, in a hallway when the earthquake struck. It felt like something hit the building. The entire building suddenly shook violently. I stopped what I was doing and looked down the hallway. I heard the shaking travel through the building from one side to the other, east to west. I knew immediately that it was an earthquake. However, after the initial jolt, I could not feel any shaking afterward and no apparent damage had been done.
The following recording was made back home while I was at work. I have set up an earthquake cam in an attempt to capture a quake on video. Unfortunately, there is no sound, but what you will see is at least three things move in the shot. (According to the clock in the video) At 8:07pm and 49 seconds, the p-wave hits, effecting the chimes and the pendulum. A 8:07pm and 59 seconds, the pendulum and the ball move, almost in unison. You have to watch for the ball closely, though. It's very subtle. For the remainder of the video, the chimes and pendulum shake until they eventually calm down.
[Magnitudes and locations are subject to change as the USGS continues to review the data.]
-Article written by Tim "Lance" Sherwood of Oceanside, Ca.
Showing posts with label california. Show all posts
Showing posts with label california. Show all posts
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At 4:02am, on Wednesday morning, a 3.1 magnitude earthquake hit 6 miles southeast of Ocotillo, California. The earthquake occurred just north of the Mexican border, in the desert, and is possibly related either to the Yuha Wells Fault or the extreme northern edge of the Laguna Salada Fault. The earthquake appears to be an aftershock of the 7.2 Baja earthquake sequence.
A 1.9 magnitude aftershock was detected just two minutes later.
The 3.1 magnitude earthquake was not reported as felt by anyone to the USGS.
The epicenter of the 3.1 quake is located in the desert where no major towns are immediately nearby. Due to the minor magnitude and rural terrain, no damage or injuries are expected.
The closest communities are Ocotillo, Ocotillo Wells, Jacumba, Seeley, Calixico, Mexicali, Santa Isabel, El Centro, Brawley, Plaster City, and the closest major US city is San Diego.
[Magnitudes and locations are subject to change as the USGS reviews the automated data.]
A 1.9 magnitude aftershock was detected just two minutes later.
The 3.1 magnitude earthquake was not reported as felt by anyone to the USGS.
The epicenter of the 3.1 quake is located in the desert where no major towns are immediately nearby. Due to the minor magnitude and rural terrain, no damage or injuries are expected.
The closest communities are Ocotillo, Ocotillo Wells, Jacumba, Seeley, Calixico, Mexicali, Santa Isabel, El Centro, Brawley, Plaster City, and the closest major US city is San Diego.
[Magnitudes and locations are subject to change as the USGS reviews the automated data.]
UPDATED 7/2/07
An earthquake with a preliminary magnitude of 4.3 struck the Watsonville area monday afternoon. The quake struck at 12:58 PM and was felt throughout the region and up into the San Francisco bay area.
There have been no injuries and damage has been limited to a few items falling off store shelves.
Two smaller quakes occured in this area last week. CLICK HERE to read our report on those quakes.
If you felt this earthquake and would like to share your story (or read other accounts), please check our message board.
Don't forget to check out our 2007 quake map to see other Northern California quakes in 2007. Our list of previous years quakes can be found on the right side of our web site.
An earthquake with a preliminary magnitude of 4.3 struck the Watsonville area monday afternoon. The quake struck at 12:58 PM and was felt throughout the region and up into the San Francisco bay area.There have been no injuries and damage has been limited to a few items falling off store shelves.
Two smaller quakes occured in this area last week. CLICK HERE to read our report on those quakes.
If you felt this earthquake and would like to share your story (or read other accounts), please check our message board.
Don't forget to check out our 2007 quake map to see other Northern California quakes in 2007. Our list of previous years quakes can be found on the right side of our web site.
The Eureka Reporter - A magnitude 5.1 earthquake rattled parts of the North Coast Sunday at 7:32 p.m. The U.S. Geologic Survey indicated the temblor was located 41 miles northwest of Eureka at a depth of approximately 6.3 miles. There was no indication that the earthquake caused any major damage or injuries. According to the U.S. Geologic Survey’s 24-Hour Aftershock Forecast Map, as of 8 p.m. Sunday, there was a low probability of aftershocks occurring in the region.
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If you felt this quake and have a story to tell, come on over to our "Quake Stories" board to share and to read other stories about this quake.
Also, be sure to check out the 2007 Earthquake map to see this quake along with other signficant quakes of 2007.
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If you felt this quake and have a story to tell, come on over to our "Quake Stories" board to share and to read other stories about this quake.
Also, be sure to check out the 2007 Earthquake map to see this quake along with other signficant quakes of 2007.
Aftershocks continue after a 4.6 earthquake shook the Sierra Nevada Mountains in Central California early Tuesday morning. The quake struck just after 12:20am (Pacific Coast time). So far there have been more than 160 aftershocks. Four of the aftershocks have been 3.0 or higher, with the largest being 3.6. The quake was preceeded by a 3.6 foreshock.
Hundreds of people throughout central California and Western Nevada have reported feeling the quake. Some of the stronger aftershocks have been felt by people in the vicinity of the epicenter.
The map here shows the area affected by this series of earthquakes.
This region of the Sierra Nevada's is very familiar with earthquakes. The last strong quake to register above 5.0 was back on May 15, 1999. When the area experienced a 5.6 quake. Even stronger damaging quakes ocurred in 1980.
Explore our Northern California historical Quake maps located on the right side of our website to see quakes in this area over the years.
Hundreds of people throughout central California and Western Nevada have reported feeling the quake. Some of the stronger aftershocks have been felt by people in the vicinity of the epicenter.
The map here shows the area affected by this series of earthquakes.This region of the Sierra Nevada's is very familiar with earthquakes. The last strong quake to register above 5.0 was back on May 15, 1999. When the area experienced a 5.6 quake. Even stronger damaging quakes ocurred in 1980.
Explore our Northern California historical Quake maps located on the right side of our website to see quakes in this area over the years.
by Heather Muller , 5/9/2007
The Eureka Reporter
“I thought I was on a boat in the ocean,” said Renee Jacobsen, manager of the Petrolia Store and former chief of the remote town’s volunteer fire department.
The magnitude 5.2 earthquake that struck 39 miles west of Petrolia shortly before 1 a.m. Wednesday “pushed you up like on top of a wave,” she said.
“And then there was the aftershock,” she said, a magnitude 4.5 temblor 17 minutes later and two miles closer to shore.
“That one was more like a sharp jolt.”
According to the U.S. Geological Survey, people reported feeling the initial earthquake as far north as Trinidad and as far south as Victorville — more than 900 miles away.
Brenda Godsey, public information officer for the Humboldt County Sheriff’s Office, said her office received only one earthquake-related inquiry and no reports of injury or damage.
The Office of Emergency Services was not activated, said OES Program Coordinator Dan Larkin.
In situations like this, Larkin said, “there’s nothing we do, because there’s nothing we can do.”
Had the incident been serious, he said, any of a range of responses would have been triggered, possibly including an emergency declaration and the activation of the Emergency Alert System, as well as various local, state and federal emergency response protocols.
Humboldt State University geology professor Lori Dengler said the earthquakes were “of interest and a low level of excitement,” adding that the two events occurred along the Mendocino Fault, which is the region’s single most active fault.
“Since 1980, we’ve had about 150 earthquakes of magnitude 4 or larger along the Mendocino Fault,” she said.
Dengler described the fault as “kind of our Mason-Dixon Line. It really divides the West Coast of the United States into two completely different tectonic areas.”
To the south is the San Andreas Fault with its side-to-side “transform” movement. To the north are the Gorda and the Juan de Fuca plates that converge along the coast and dive down to create the vertical movement characteristic of the Cascadia Subduction Zone.
The Mendocino Fault itself, where Wednesday’s earthquakes occurred, moves horizontally, Dengler said.
“So if you had been standing south of the Mendocino Fault, and if there were no water in the ocean and you could have actually seen what was going on, you would have seen the land north of the fault move maybe half a foot closer to the coast,” she said.
But it could have been worse.
“In the 1906 earthquake, had you been on the San Andreas Fault and looked across to the other side, you would have seen it move more than 20 feet in some places,” she said.
Dengler has long said the North Coast is overdue for a damaging earthquake.
“The point I really like to make is that this is the time to take action to reduce your hazards. It can be something as simple as that huge potted plant on a bookshelf above your bed. Maybe there’s a better place for it. Develop an emergency plan for your family. Make sure your hot water heater is secured to a structural element of your house.
“They’re small things, but they can make a big difference.”
On shaky ground: Significant North Coast earthquakes of the past 30 years
+ June 14, 2005 6:50 p.m.
Magnitude 7.2, centered 97 miles west of Trinidad
Felt lightly but resulted in tsunami warning for the entire West Coast
No reports of injury or damage
+ Feb. 18, 1995 8:03 p.m.
Estimated magnitude 6.5, centered 80 miles west-southwest of Eureka
No reports of injury or significant damage
+ Dec 26, 1994 6:10 a.m.
The Eureka Earthquake
Estimated magnitude 5.4, centered 12 miles west-southwest of Eureka
Minor injuries reported and damages estimated at more than $2.3 million
+ Sept. 1, 1994 8:15 a.m.
The Mendocino Fault Earthquake
Estimated magnitude 6.9, centered approximately 90 miles west of Cape Mendocino
No reports of injury or significant damage
+ April 25, 1992 11:06 a.m.
The Ferndale Earthquake
Magnitude 7.1, centered near Petrolia
Followed by aftershocks of magnitude 6.6 and 6.7 near Cape Mendocino
Damage estimated at $60 million, resulted in federal disaster declaration
+ Sept. 17, 1991 12:29 p.m.
The Honeydew Earthquake
Estimated magnitude 6.1, centered 13 miles south-southeast of Cape Mendocino
More than 60 percent of Honeydew residents reported structural damage
+ Nov. 8, 1980 2:27 a.m.
The Trinidad Earthquake
Magnitude 7.1, centered 30 miles west of Trinidad
Freeway overpass south of Eureka collapsed
Regional damages estimated at $1.75 million
Source: Humboldt State University Geology Department’s Humboldt Earthquake Education Center
The Eureka Reporter
“I thought I was on a boat in the ocean,” said Renee Jacobsen, manager of the Petrolia Store and former chief of the remote town’s volunteer fire department.
The magnitude 5.2 earthquake that struck 39 miles west of Petrolia shortly before 1 a.m. Wednesday “pushed you up like on top of a wave,” she said.
“And then there was the aftershock,” she said, a magnitude 4.5 temblor 17 minutes later and two miles closer to shore.
“That one was more like a sharp jolt.”
According to the U.S. Geological Survey, people reported feeling the initial earthquake as far north as Trinidad and as far south as Victorville — more than 900 miles away.
Brenda Godsey, public information officer for the Humboldt County Sheriff’s Office, said her office received only one earthquake-related inquiry and no reports of injury or damage.
The Office of Emergency Services was not activated, said OES Program Coordinator Dan Larkin.
In situations like this, Larkin said, “there’s nothing we do, because there’s nothing we can do.”
Had the incident been serious, he said, any of a range of responses would have been triggered, possibly including an emergency declaration and the activation of the Emergency Alert System, as well as various local, state and federal emergency response protocols.
Humboldt State University geology professor Lori Dengler said the earthquakes were “of interest and a low level of excitement,” adding that the two events occurred along the Mendocino Fault, which is the region’s single most active fault.
“Since 1980, we’ve had about 150 earthquakes of magnitude 4 or larger along the Mendocino Fault,” she said.
Dengler described the fault as “kind of our Mason-Dixon Line. It really divides the West Coast of the United States into two completely different tectonic areas.”
To the south is the San Andreas Fault with its side-to-side “transform” movement. To the north are the Gorda and the Juan de Fuca plates that converge along the coast and dive down to create the vertical movement characteristic of the Cascadia Subduction Zone.
The Mendocino Fault itself, where Wednesday’s earthquakes occurred, moves horizontally, Dengler said.
“So if you had been standing south of the Mendocino Fault, and if there were no water in the ocean and you could have actually seen what was going on, you would have seen the land north of the fault move maybe half a foot closer to the coast,” she said.
But it could have been worse.
“In the 1906 earthquake, had you been on the San Andreas Fault and looked across to the other side, you would have seen it move more than 20 feet in some places,” she said.
Dengler has long said the North Coast is overdue for a damaging earthquake.
“The point I really like to make is that this is the time to take action to reduce your hazards. It can be something as simple as that huge potted plant on a bookshelf above your bed. Maybe there’s a better place for it. Develop an emergency plan for your family. Make sure your hot water heater is secured to a structural element of your house.
“They’re small things, but they can make a big difference.”
On shaky ground: Significant North Coast earthquakes of the past 30 years
+ June 14, 2005 6:50 p.m.
Magnitude 7.2, centered 97 miles west of Trinidad
Felt lightly but resulted in tsunami warning for the entire West Coast
No reports of injury or damage
+ Feb. 18, 1995 8:03 p.m.
Estimated magnitude 6.5, centered 80 miles west-southwest of Eureka
No reports of injury or significant damage
+ Dec 26, 1994 6:10 a.m.
The Eureka Earthquake
Estimated magnitude 5.4, centered 12 miles west-southwest of Eureka
Minor injuries reported and damages estimated at more than $2.3 million
+ Sept. 1, 1994 8:15 a.m.
The Mendocino Fault Earthquake
Estimated magnitude 6.9, centered approximately 90 miles west of Cape Mendocino
No reports of injury or significant damage
+ April 25, 1992 11:06 a.m.
The Ferndale Earthquake
Magnitude 7.1, centered near Petrolia
Followed by aftershocks of magnitude 6.6 and 6.7 near Cape Mendocino
Damage estimated at $60 million, resulted in federal disaster declaration
+ Sept. 17, 1991 12:29 p.m.
The Honeydew Earthquake
Estimated magnitude 6.1, centered 13 miles south-southeast of Cape Mendocino
More than 60 percent of Honeydew residents reported structural damage
+ Nov. 8, 1980 2:27 a.m.
The Trinidad Earthquake
Magnitude 7.1, centered 30 miles west of Trinidad
Freeway overpass south of Eureka collapsed
Regional damages estimated at $1.75 million
Source: Humboldt State University Geology Department’s Humboldt Earthquake Education Center
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