Two Small Tremors Gently Shake Altadena This Morning

Did You Feel the Earth Move -- Just a Little Bit?

According to the US Geological Survey website, two small earthquakes -- magnitude 2.2 and 2.1 -- occurred within two miles of west Altadena at 11:48 a.m. 

Consider it a subtle nudge to review one's emergency preparedness plan and supplies.

Dale Frey July 05, 2012 at 07:52 PM
Big Bear had a 3.5 also......seems to be a trend.
Karin Bugge July 05, 2012 at 08:09 PM
Did you feel it, Dale? I didn't, but my dog started barking at about this time for no particular reason. Although he often barks for no particular reason.
Natalie July 05, 2012 at 08:42 PM
If you felt it, fill in the "Did you feel it?" questionnaire, linked on the USGS website. Seems it was in the area of Devil's Gate dam or JPL?. I was walking my dog down there at the time, but didn't feel anything.
Liz H. July 05, 2012 at 09:31 PM
Your dog! What a character! I laughed out loud when I read this.
Angela Odom July 06, 2012 at 02:54 AM
Wow, just looked at the USGS site and followed the Google links for the locations. One was on Seco Street (2.1), another on Amanda Drive (2.1) and the first one (a 1.0) happened in the golf course. All of them were around the Rose Bowl. What kind of fireworks display did they have there last night.
ANALILY PARK July 06, 2012 at 04:52 AM
A gentle reminder of the inevitable and that matter is constantly moving.........
Tim Blewett July 06, 2012 at 01:33 PM
Actually, they are temblors, not tremors.
Isabella Baumfree July 06, 2012 at 03:18 PM
I think there's a fault line that runs through Altadena - Raymond Fault line, an offshoot of the San Andreas Fault Line - does anyone know?
Leslie Aitken July 06, 2012 at 04:10 PM
Isabella -- it is probably my weird sense of humor -- but I started to laugh at the irony of your statement, "I think there's a fault line that runs through Altadena." Touche! I think the name of it is, "Your Fault". (not yours personally -- but the collective use of the play on words). HA HA HA!
Robby July 06, 2012 at 04:14 PM
Hi Isabella! The Raymond Fault is south of us - it's actually closer to San Marino than it is to us up here in Altadena. You know how it's sort of hilly near the Huntington? And how it's almost a bluff near the 110 and Fair Oaks in South Pas? Raymond Fault escarpment.
Isabella Baumfree July 06, 2012 at 05:02 PM
Thanks Robby, interesting. Leslie, I'm glad that I gave you a reason to laugh laughter is like medicine -
Angela Odom July 06, 2012 at 08:02 PM
In Altadena there is the B section of the San Gabriel Fault. It runs behind JPL, down into Altadena (your cross it at the bridge on Lincoln just as you leave Altadena Drive), and continues through Altadena, up to Loma Alta Park and around the mountain line through some communities. This section of the fault could produce a magnitude 7.2 to 7.6 quake. When the USGS dug a trench up at Loma Alta some years ago, their study showed the last quake shifted as much as 13 feet. Now that's a ride. Fascinating study. You can read more about the research and trenching info here : http://www.geology.cwu.edu/facstaff/charlier/currentprojects/los_angeles_sum.html
Natalie July 06, 2012 at 08:11 PM
It's just occurred to me that many of the waterfalls on the front face are about 13 feet high - Millard, Bailey, Eaton and Sturtevant. I thought that might have been due to a quake, but didn't realize it was on this fault.
Robby July 06, 2012 at 09:48 PM
Fun fact! Streams and ponds often follow fault lines, because the ground is nice and mushed up there, allowing for greater erosion. Also, you'll find springs and artesian wells where a fault has uplifted the terrain - the horizontal water table will run smack into an impermeable layer of rock that has been lifted up by a fault, causing the water to rise to the surface. You can also spot totally different types of rock next to each other, like a light-colored crumbly rock next to a dark, hard rock - that is sometimes a fault. Sounds like Natalie has a good eye for terrain! That's a gift, you know...not everyone has that! =)
Elizabeth Nazarian July 06, 2012 at 10:00 PM
What an education and laughter at the same time!!!!!!!!! Thanks to all!!!
Isabella Baumfree July 06, 2012 at 10:13 PM
Angela, thank you for that information. I'll look it up on the website
Ericka July 06, 2012 at 10:54 PM
How funny! I was home when it happened and Greg asked me later if the dogs had barked. First I said no, and then I said, well, maybe - they often bark for no reason and I don't even hear it anymore!
Liz H. July 07, 2012 at 12:15 AM
Tremor is correct, as is temblor.
Tim Blewett July 07, 2012 at 01:43 PM
Temblor is the earthquake event. A tremor is the shaking. The tremor is due to the temblor.
Tim Blewett July 07, 2012 at 01:53 PM
The faults are not directly related. There are literally dozens of faults in the area. Some are vertical faults resulting in horsts and grabens. The fault located directly behind Washington Jr. High (the name may be different now) is a vertical fault. I believe the Raymond Fault is also vertical. The San Andreas located on the north side of the San Gabriels is a lateral thrust fault. The west side has moved north about 30 miles in the last 30,000,000 years. This can be seen where the rocks in the Devil's Punch Bowl Formation are split. One portion is in the Devils Punch Bowl, and the other portion is in Cajon Pass.
lonnie fehr July 07, 2012 at 05:33 PM
so ,,whos ,,, fault was this ,,, lol
Tim Blewett July 07, 2012 at 06:54 PM
Draw a line from Pacoima Creek, Big Tajunga, Mill Creek, Upper Arroyo, West Fork of the San Gabriel River and East Fork of the San Gabriel. When I took Geology at PCC in 1960/62 I believe the thoughts were that the fault was inactive; however, faults and volcanoes have a habit of becoming active when you least want them to.


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