Why are Earthquakes Felt So Widely over the Eastern US?

3.9 Earthquake in Newhall

Several weeks ago, I woke up to the sound of my "Quakealarm" ringing, feeling a very small rolling motion a few seconds later. After that I immediately went back to sleep. I later checked USGS and found out that I awoke to a magnitude 3.9 earthquake near Newhall, CA. The epicenter was about 40km away from my house.

Several weeks earlier, on the East Coast, there was a magnitude 4.0 earthquake in Southern Maine. My friend who was in Connecticut,  felt the shaking (she is a native Californian, so she has felt many earthquakes). The shaking amount was a little more (About III-IV) than the amount I had felt in the earthquake (About II) in Newhall. Interestingly, my friend was over 200km away from the epicenter. How is an earthquake on the East Coast felt farther than a similar size earthquake with a similar depth, in California?

4.0 Earthquake in Maine

Well, the answer is simple.

In California the geology of the earth is very different than the geology in the East Coast. In California, the ground is less dense than on the East Coast, where the ground is more solid. Lucy Jones in USGS has said many times to TV reporters: "A solid bell rings more than a cracked bell."

Wacky Weather in West LA- 11/10/12

Clouds Looking West
(Image Property of Socal Earth Science Blog)

November 10, 2012: just before 5pm a small row of clouds, passed through the LA Basin on a perfectly sunny and otherwise cloudless day. In my location, just north of Playa Vista, a period of light rainfall and drizzle occurred for approximately twenty minutes. Only a trace of rain was recorded in my rain gauge.

El Nino Watch Issued- What is El Nino?

Courtesy of the NWS

UPDATE 12/9/12: The NWS now forecasts only Neutral conditions

The National Oceanic and Atmospheric Association have gone into El Nino Watch, which means that El Nino Conditions are likely in the near future (this winter). El Nino is when the Pacific Ocean near South America is experiencing warmer than average temperatures, while La Nina is when the temperatures of the Pacific Ocean near South America are cooler than average.

Courtesy of the NWS

Well, you may ask, how do El Nino and La Nina affect SoCal?

During La Nina conditions, the the Pacific Northwest often receives a large amount of rainfall and cool temperatures during the winter, while SoCal usually stays dry (leads to drought when La Nina lingers for long periods of time).

During El Nino conditions, the southern part of the United States (including SoCal), receives above average amounts of rainfall with an increased probability of severe weather. This is because the Pacific Jet Stream hovers over the southern part of the United States (instead of being more variable) bringing more storms systems south to SoCal.

So this winter, if you live in SoCal, prepare for cooler temperatures and more rain, this winter.

Information retrieved from:
www.noaawatch.gov

Fire Near The Getty Center- 9/14/12

As of 5:20pm on 9/14/12 several wildfires have broken out in the Santa Monica Mountains.
Two of the three fires are small, one of which was a transformer fire on Mulholland Drive, and the other of which was most likely an arson fire on Coldwater Canyon Road.


The largest of the fires is currently spreading rapidly near the eastern side of the 405 freeway, and is located near the Bell Air Estates. The largest fire was reported at 3:36pm and is currently being fought using firefighting helicopters, and as of now, by "super scoopers." The fire is approximately 25 acres, but only voluntary evacuations have occurred.

The 405 freeway has just been closed off near Getty Center Drive and the Getty Center has closed early due to the fire. Traffic has been backed up all the way to the 90 freeway.

Temperatures are a searing 97 degrees in the area, and humidity is a mere 13%, but wind speeds are quite low, so the fire near the 405 will most likely not spread too far, and will be contained shortly.

Second Earthquake in Beverly Hills (Magnitude 3.4) - 9/7/12

Early this morning (3:09am), many people in Beverly Hills and throughout the "Westside" were jolted awake by a magnitude 3.4 earthquake (downgraded from 3.5). The earthquake was located most likely near or on the Santa Monica Thrust Fault (where the proposed westside subway extension will be built), in Beverly Hills. The earthquake had an intensity of IV, but was registered as intensity V on DYFI (Did you feel it). The earthquake was felt as a long-lasting jolt in my location in Del Rey (where in the world is that?).
 

My Recent Detections on QCN. The Highlighted Blue Detection is from the Earthquake.
 The Earthquake Number (Not Magnitude) Can be Seen on the Far Right.
The Earthquake Significance and Magnitude are Seen Toward the Left.

I am happy to say that my QCN Sensor did record the jolt. Please check my earlier post on the Quake-Catcher Network (August 2012) for more information on the network.

If you felt the earthquake, please provide the shaking strength in your location at:
http://earthquake.usgs.gov/earthquakes/eventpage/ci15211897#dyfi_form

3.2 Earthquake Beverly Hills, CA- 9/3/12

Last night at 3:26am, there was a magnitude 3.2 earthquake (Intensity IV) (downgraded from 3.3) in Beverly Hills, CA. The earthquake was most likely located on the Santa Monica Thrust Fault, and had a depth of 1.5 miles. The quake was felt throughout the "Westside" (not only SM. heh heh.) and woke many in the area.

If you felt the earthquake, please report the shaking in your location at:
http://earthquake.usgs.gov/earthquakes/eventpage/ci15210193#summary

Snow, in The LA Basin?

Snow in Glendale in 1949
Image Courtesy of the Los Angeles Public Library

Snow in Pasadena 1949
Image Courtesy of the Los Angeles Public Library

When most people think of SoCal, they think of hot, sunny beaches with palm trees and tourists. Well, has anyone ever thought of the palm trees engulfed in a blanket of snow? You may think that it is impossible to snow in low altitude SoCal. But did happen. And it still is possible, with cold storm systems. In January 2007 a cold storm system blew threw Los Angeles and dropped a measurable amount of snow in Malibu, and the Santa Monica Mountains.

Similar, but more significant storm systems found their way into the LA Basin and produced measurable snowfall throughout the city. Such instances occurred in the years 1932 and 1949.

Yet Another Earthquake in Yorba Linda (Magnitude 4.1)- 8/29/12

Courtesy of USGS

Yesterday, there was another earthquake in Yorba Linda, CA. It was a magnitude 4.1 earthquake (Intensity V) and had a depth of 5.7 miles (slightly deeper than the earthquakes preceding it). Because of its slightly lower magnitude and depth, it was not felt as widely or as strongly as the earthquakes preceding it. Nevertheless, it was the third earthquake greater than magnitude 4 that occurred in the area recently.

If you felt the earthquake, please go to: http://earthquake.usgs.gov/earthquakes/eventpage/ci15207433#dyfi_form
to report the amount of shaking that you felt in your location.

Earthquake Swarm in Brawley, CA- 8/26/12

 

Shakemap of the 5.5 Earthquake

The Quake

In the past few days there has been over 1791 earthquakes ranging from not felt (Intensity I) to magnitude 5.5 and 5.3 (Intensity VII and VI) near Brawley, CA. They were felt throughout Southern California and Arizona, and caused damage ranging from broken windows, to large cracks in buildings. Electricity was lost for several hours in places, but was soon returned. The earthquakes were located on the Brawley Seismic Zone near the US-Mexico Border. Footage of the earthquakes can be seen to the right.

Intensity vs. Magnitude

Ok. What is the difference between magnitude and intensity? Magnitude is measured in Movement Magnitude and Richter Scales. The Richter Scale is a base-10 logarithmic scale that measures the amplitude of an earthquake's waves.

What is base-10? Well, base ten means that a magnitude 1 is theoretically 10 times larger than a magnitude 0 and a magnitude 2 is 10 times larger than a magnitude 1 and a magnitude 3 is 10 times larger than a magnitude 2, and so on. The difference between a magnitude 5 and 9 is 10x10x10x10=10,000 times. So a magnitude 5 is nothing compared to a magnitude 9 earthquake. Magnitude is the measurement of the energy released at the epicenter.

Now, on to intensity. Intensity is the measurement of the ground motion, or the effect of the earthquake in a given location. For example, an intensity III earthquake's effects include: being felt by most people indoors, and with vibrations being similar to a large passing truck. For the recent 5.5 earthquake, which was intensity VII, effects include: difficult to stand, furniture broken, negligible damage in well built structures, and slight to moderate damage in ordinary structures.

The Ballona Wetlands Restoration Project

One of the Original Alternatives 
"Alternative 5"
Later Revised Because it Was Too Drastic
Courtesy of SMBRC

The Ballona Wetlands Restoration Project is a planned restoration of the Ballona Wetlands by the Santa Monica Bay Restoration Commission and Foundation. The Plan will restore the tidal flow into the degrading wetlands near Playa Del Rey and Marina Del Rey, and will remove the concrete levees of the Ballona Creek that which was channeled in 1938.

Since 2008 SMBRC created five alternative means of restoration, which were later narrowed it down to two  revised possible plans: "alternative 4", and "alternative 5".

Alternative four involved creating many culverts from Marina Del Rey into the northern portion of the wetlands, creating a tidal influence into the degraded section. It also included more culverts into the southern half of the wetlands, also increasing its tidal influence. This alternative did not include the removal of the levees in the creek.


Alternative 4
Courtesy of SMBRC

Alternative five, which was revised from a major diversion of the creek into a less drastic measure. It involved the removal of most of the levees and the diversion of the creek into a more meandering route, into the northern and southern portion of the wetlands. This alternative involved changing the path of a portion of Culver Blvd. in the wetlands. This alternative is considered by many as "risky" due to the exposure of the wetlands to the direct influence of the runoff and trash from the creek.


Alternative 5
Courtesy of SMBRC



The Current Preferred Alternative
Courtesy of SMBRC

Alternative five was later thought to be the most effective alternative in restoring the wetlands, and alternative four was ruled out. In January 2012 funding for the project was approved, and the alternative was revised even more. The cost of changing the path of Culver Blvd. was found to be very costly, so it was ruled out. Instead, the path of the creek would be changed slightly, and a levee on the north side of Culver Blvd. would be built. Also it was decided that the portion of the wetlands south of Culver Blvd. would be made into a "managed marsh" that would only be fed by culverts that could manage the amount of sea water entering, to prevent the over-flooding of the portion of the wetlands due to sea level rise.

Information Retrieved from:
http://www.santamonicabay.org/BWRP/bwrpdocuments.html

The Quake-Catcher Network (QCN)

The Quake Catcher Network is a project created by Stanford University the US Geological Survey, and  several other organizations. QCN is a "Citizen Science" Project, which involves countless USB Sensors, as well as Laptop Accelerometers, to create a network of low-cost seismometers worldwide. The project's goal is to to improve earthquake monitoring, and earthquake awareness.

The performance of different QCN
Accelerometers, as well as compatible laptops

You can take part in the system of accelerometers by signing up for a USB Sensor for $49, or if you are a teacher, for $5. A word of warning for people with newer Macs. I had some sensor issues, but when I used my PC it worked with no problems.

If you have a laptop with an accelerometer, you can set up QCN immediately without purchasing a USB Sensor, by downloading BOINC at the QCN website. Unfortunately, laptops can only pick up larger earthquakes that happen when your computer is on idle.

QCN was able to record both of the 4.5 Yorba Linda Earthquakes, and was also able to record countless earthquakes worldwide in the past few years.

Images and information retrieved from:
www.qcn.stanford.edu

Magnitude 3.4 Earthquake Near Manhattan Beach- August 11, 2012

This morning at 8:33am PST, a mild magnitude 3.4 earthquake struck off of the coast, near Manhattan Beach. It was felt as intensity III near the epicenter and was felt as intensity II in most of the LA Basin. It had a depth of 5 miles, and no damage was reported.

If you felt the earthquake, report the shaking strength at your location at: http://earthquake.usgs.gov/earthquakes/eventpage/ci15190937#dyfi_form 

It's Sizzling in Southern California

This week, extremely high temperatures have, and are expected to, be imminent in the area this week. Temperatures in the coastal and mountain areas are expected to be between 85 and 112 degrees Fahrenheit, while in the Deserts of Southern California, temperatures will be between 110 and a blistering 125 degrees (Death Valley). Record-breaking temperatures were recorded.

Luckily, it appears that today was the peak of the heat wave, and that there will be a slow cooling trend throughout the rest of the week.

The monsoonal moisture that came from the south made its way into Southern California, creating high humidity and isolated thunderstorms in the deserts and mountain areas.

For more information visit:
www.noaawatch.gov 

Second Magnitude 4.5 Earthquake Near Yorba Linda- August 8, 2012

The Quake

This morning at 9:33am, a Magnitude 4.5 earthquake struck near Yorba Linda, California. It caused moderate shaking throughout the area surrounding the epicenter and caused Mild to Weak Shaking throughout the Greater Los Angeles Area. The earthquake is most likely an aftershock to the earthquake last night. Unlike the earthquake last night, it was shallower, at a depth of only 5 miles, causing it to have slightly stronger shaking than the main shock.

Reflecting off of the Quake

Update 11/10/12: Doug Given, one of the leaders of the Shakealert program stated that during the two earthquakes Caltech received 9 seconds of warning on the first quake and 4 seconds on the second quake.

If this earthquake had been larger, and an earthquake early warning system had been in place, a short warning could have been given to the Los Angeles Area. However there would have been a blind zone where no warning could be given.

The Chino Hills Earthquake of 2008 occurred in a similar location, and had there been a functioning system at the time, and had the earthquake been larger, a warning could have been given. Please Note that the warning would have been shorter than shown because would take at least 5 seconds after detection to process the earthquake before sending out a warning.

The video of the ShakeAlert System was created by the US Geological Survey, Caltech, UC Berkley, and the other organizations creating the system.

The amount of warning time given depends on your distance from the epicenter. The farther you are from the epicenter, the more warning you would receive. The problem is, that the farther you are from the epicenter, the shaking is usually weaker (unless an earthquake occurs along an entire fault).

The amount of warning that could be given for a large earthquake on the southern San Andreas Fault is shown at the right. Almost an entire minute of warning could be given to the Los Angeles Area.

Although an earthquake early warning system could help save lives during an earthquake, there is little funding for the system, and very few people have even heard of them.

Please see my older post on earthquake early warnings from July 2012

For more information visit:
http://www.eew.caltech.edu/

Magnitude 4.5 Earthquake Near Yorba Linda- August 7, 2012

Last night at 11:23pm PST, a magnitude 4.5 earthquake struck near Yorba Linda, California. It had a depth of 6.5 miles and produced Moderate Shaking (Intensity V) in the areas near the epicenter. Mild to Weak Shaking was felt throughout the Greater Los Angeles Area, and was felt as far away as the U.S./Mexico Border.
If you felt the earthquake or didn't feel the earthquake go to: http://earthquake.usgs.gov/earthquakes/eventpage/ci15189073#dyfi_form
to report the shaking strength where you were during the earthquake.

For more information, visit:
http://earthquake.usgs.gov/earthquakes/?source=sitenav