LOCATION
The City of Industry has purchased over 5,700 acres of land outside its city limits. Their ownership, known as Tonner Canyon, lie between the 60 freeway near Pomona and runs in a crescent shape all the way to the 57 freeway near Brea. Click the link to Industry property photos. Follow this link to see a Map of Industry's lands.

INDUSTRY'S PLAN
The City of Industry has proposed four massive dams in Tonner Canyon upstream of Brea. These dams require numerous saddle dams to prevent flooding of neighboring homes and would lie near an active fault line. Click the link for an aerial view of these plans.

EARTHQUAKE FAULTS IN THE PUENTE-CHINO HILLS
There are three main faults that have created the Puente-Chino Hills.  These faults are the Whittier, Chino and Elsinore Faults. 

Whittier Fault
The Whittier Fault, generally runs from the 91 freeway northwest through the along the foothills of Yorba Linda to the mouth of Tonner Canyon and on to the Whittier Narrows Recreation Area. This fault created the Puente-Chino Hills.  The last major release near this fault was a magnitude 5.9 on October 1, 1987.  This earthquake caused $358 million in property damage and experts estimate that this fault is capable of a magnitude 6.0 - 7.2 earthquake. Follow this link to see a map of the Whittier Fault on the United States Geological Survey website.   The Whittier Fault is a red line labeled 126a - Elsinore fault, Whittier section. There you can click on the 126a to read about the fault line. (Hit the back button to return to Hills For Everyone's website). 

Chino Fault
The Chino Fault runs generally from the 91/71 freeway intersection north to the 60 freeway.  This fault created the eastern side of the Chino Hills.   Seismologists estimate that this fault is capable of a magnitude 6.0 - 7.0 earthquake. Follow this link to see a map of the Chino Fault on the United States Geological Survey website.  The Chino Fault is a yellow lined labeled 126b - Elsinore fault zone, Chino section.  There you can click on the 126b to read about the fault line.  (Hit the back button to return to Hills For Everyone's website).

Elsinore Fault
The Elsinore Fault runs from the 91 freeway south to the 5 freeway in San Diego and this fault created the Santa Ana Mountains.  Its last major release was May 15, 1910 with a magnitude 6.0 quake. It is estimated that this fault is capable of a magnitude 6.5 - 7.5 earthquake. Follow this link to see a map of the Elsinore Fault on the United States Geological Survey website.  The Elsinore Fault has three segments colored light blue, dark blue and mint green lined.  The Whittier Fault is labeled 126c, 126d and 126e - Elsinore fault zone with various sections.  There you can click on the 126c, d or e to read about the fault line.   (Hit the back button to return to Hills For Everyone's website). 

To learn more about earthquakes and local faults visit:

• The United States Geological Society
• Southern California Earthquake Data Center
• CalTech Seismological Laboratory

EARTHQUAKES AND RESERVOIRS
International symposiums have been held to discuss the effects of reservoirs on earthquake faults. This phenomenon is called “Reservoir Induced Seismicity” or RIS.

Facts About Reservoirs
Here are some basic facts about reservoirs:
    1. Reservoirs are built in valleys.
    2. Valleys are areas that have been eroded over time.
    3. Valleys indicates that uplift by faulting (earthquakes) has occurred in the region.
    4. Therefore when water is placed in a valley for a reservoir, it is on or near a fault line.

How Reservoirs Impact Faults
There are two ways that earthquakes can occur when a reservoir is built near/on an earthquake fault.  First, when water is added to a valley and on/near a fault line there is additional weight to the earth's surface -- this in turn changes the stress of the fault.  When water is added the amount of stress increases on the fault line.  Second, and slightly more technical, the water changes the amount of space (porosity) of the underlying soil.  When this occurs the ground becomes saturated and more unstable.  This phenomenon is known as Reservoir Induced Seismicity or R.I.S.

When will the Earthquake Happen?
According to experts, it is most likely that an earthquake will occur almost immediately after filling the reservoir.  If there is a delay of a few years it would be because of the saturation of the soil took longer... meaning if the rock was not very porous, it would take longer to become saturated and therefore longer to change the stability of the surrounding soil.

Recipe for an Earthquake
In order to trigger an earthquake the following will occur:
    1.  A reservoir built on/near an active fault can cause either:          
               A. The fault line to be stressed by the weight of the water  -or-
               B.  The ground's stability changes when water is added to the surface.
    2.  The pressure becomes too great or the ground too saturated and the fault releases
                producing an earthquake.

PLACES SCIENTISTS BELIEVE RIS HAS ALREADY OCCURRED

M = Magnitude


To learn more about Reservoir Induced Seismicity visit:

• Seismology Research Centre (Australia)
• References on Reservoir Induced Seismicity
• United States Geological Survey
• Reservoir Induced Research Group (Canada)

WHAT DOES THIS MEAN FOR INDUSTRY'S PLANNED RESERVOIR?
Since geologists know that the Whittier extension of the Elsinore Fault is an active fault line and that water increases the stress on a fault and/or changes the stability of the ground beneath the reservoir, the danger posed by the Industry reservoirs is real.  Should an earthquake occur on the Whittier Fault and should the dam break the 275,000 acre feet of water would inundate large portions of the City of Brea and Fullerton, including Brea Junior High and the downtown. More specifically those living along Brea Canyon Road and Brea Blvd., will be inundated with water minutes after a large earthquake.  This is a disaster that should be avoided entirely. 

Should a saddle dam break, some of which are proposed to be as high as 120', there is no doubt neighborhoods in Diamond Bar will be flooded as well.