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Roger Weller, geology instructor

Earthquakes-Los Alamos, New Mexico
by Catherine Kilgore
Physical Geology
Fall 2006

How to Create a New Great Divide
In One Easy Lesson!) 

          Earth, The Big Blue Marble, Terra Firma, or Gaia, whatever name you use for the planet we live on, most of us can agree that it has a dynamic, constantly changing surface.  As human inhabitants of this planet, we often make the mistake of thinking we have the power to control those changes, particularly with regard to geological events.  In the United States we ignore or downplay the dangers of sleeping giants like fault lines and volcanoes.  We build our cities, houses, hospitals, and other structures very near to, or on top of them.  These areas have beautiful views, and besides, earthquakes and volcano eruptions happened here millions of years ago, all that is over now, right? 

Mount St. Helen’s, Washington

Photo Courtesy Volcano World – USGS Scientist May 18, 1980 

          Wrong!  The eruption of Mount St. Helens in Washington State on May 18, 1980 was quite a shock to many people.  The earthquakes frequently reported along the San Andreas Fault in California have become something of a national joke.  Although there have been some fairly large quakes along the fault, there has not been an earthquake here in our lifetimes equal to the San Francisco Earthquake of 1906, which was estimated at anywhere between 7.7 and 8.3 on the Richter Scale.  Even the devastating Loma Prieta Earthquake of October 17, 1989 during the  World Series only measured at 6.9, a strong quake, but not near what the San Andreas Fault is capable of producing.  While geologic events on the West Coast usually get at least some media attention, we don’t often hear that the West Coast is not the only area of the country where faults and dormant volcanoes are capable of producing devastating geologic events.

Loma Prieta Earthquake

Loma Prieta Earthquake
Photo Courtesy Microsoft
® Encarta®
David Weintraub/Photo Researchers, Inc.

          One of those areas is the State of New Mexico.  You may be asking how an earthquake or volcanic eruption in New Mexico could possibly be a national disaster.  It is not highly populated by comparison to most states, it is mostly desert, what could be such a problem?  While these things may be true, they also have something no other state has, Los Alamos National Laboratories (LANL).  While you may have heard some things in the news lately regarding LANL, it is very likely you haven’t heard everything.  

          LANL is located in the small town of Los Alamos, a beautiful area of northern New Mexico south of the Colorado border.  It is also located in a volcanic field and in one of the most active fault zones in the country.  Los Alamos is on the western edge of the Rio Grande Rift, 4 miles from the Jemez Caldera, 5 miles from the Valles Caldera, and about the same distance from the Potrillo Volcanic Field.  Valles Caldera is one of three of the largest, youngest, and most potentially active calderas in the United States.  Calderas form when magma explodes out to the surface.  The ground collapses into the empty space left behind by the magma and creates a depression, which can be more than 20 kilometers wide and several kilometers deep.  The area around Los Alamos has active hot springs and fumaroles created by ground water heating due to three large magma bodies under the calderas and volcanic fields.  The long-term stability of these magma bodies is unknown.    

Soda Dam Hot Spring in Jemez Caldera Area

Photo Courtesy Volcano World – Geoffrey Johnson Photographer 

          In addition to volcanoes, the area is also home to faults capable of producing large earthquakes, Rendija Canyon, Guaje Mountain, and the largest, The Pajarito Fault Zone.  Since 1873, six earthquakes registering above 5.0 have been recorded in the Los Alamos area.  The largest was the Cerrillos quake, which registered at 5.5 to 6.0.  Between 1973 and 1994, 672 small quakes were recorded, the largest a 3.0.  So far, in 2006, LANL has reported dozens of small magnitude earthquakes with the smallest recorded at 1.0 and the largest at 2.4.  They have also noted an increase in activity at the Caja del Rio Plateau near the Buckman Wells Field, the water supply for nearby Santa Fe, New Mexico.  This increase in activity may be related to geologists’ findings that the water table levels in the Los Alamos and Santa Fe areas are dropping significantly.

Valles Caldera and Environs

Photo Courtesy Santa Fe, New Mexico Library – LANDSAT image USGS   

          Knowing all of this, you may be thinking that surely the Federal Government would not allow a nuclear testing and processing facility to continue operation in a geologically active area if it were not safe.  Obviously, it would be in their best interest to monitor the geologic activity of the region and upgrade the facilities to withstand the strongest earthquake possible in the area, or move it completely.  Well, at least they are monitoring seismic activity.

          Although the LANL was created in 1942, no seismic activity was monitored in the area until 1973.  In order to be sure other countries were complying with the nuclear test ban treaty, seismographic instruments were installed at LANL to watch for activity consistent with nuclear testing.  Eventually, someone thought that the local seismic activity could pose a problem at the facility.  All of the area faults were mapped that could be, and it was discovered that the Rendija and Guaje faults run right through the LANL compound and under several of the buildings.  Two of the buildings located on faults are the plutonium processing facility and the nuclear materials storage facility. 

Los Alamos Area Satellite Image

Image Courtesy National – USGS/EROS Data Center 

          This created a huge problem for the Department of Energy (DOE) and the National Nuclear Security Administration (NNSA).  Since they cannot deny the existence of the faults, they instead downplay the amount of seismic activity related to the faults and the possibility that they could cause a nuclear disaster.  The fact is, a nuclear disaster could happen at LANL.  According to the nuclear watchdog organization, The Los Alamos Study Group, at least nine LANL buildings have failed seismic evaluations, including the nuclear materials storage facility and the plutonium production facility; again, both buildings are located on top of faults.  Additionally, several buildings would have major systems damage such as inoperable fire suppression systems if a major event would occur.  LANL’s own geologists have concluded that in the event of a large earthquake, the LANL and Los Alamos County would be isolated by road from emergency crews due to mass wasting and surface rupture.  Notably absent in any discussions among LANL, the DOE, and NNSA regarding such an emergency situation is how vulnerable Los Alamos Medical Center is.   

          What is more frightening is that the DOE has chosen LANL as the site of all plutonium processing and manufacturing for U.S. nuclear weapons, the end product being atomic bomb cores, known as “pits”.  This decision was based on a risk assessment that a large seismic event would only occur every 100,000 years, and that if such an event would take place, less than 610 milligrams of plutonium would be released from the facility.  Due to increased production, planned storage of plutonium at the facility, at last word, is to be 6,600 kilograms.  There has been no environmental analysis and no significant upgrade to the existing buildings is expected.   

          If the production of plutonium isn’t enough reason for alarm, it should also be noted that Area G at LANL is the largest nuclear waste dump in New Mexico and its surrounding states.  LANL intends to expand Area G indefinitely as pit production increases.  Also notable is that the dump is located next to natural springs, is not lined to prevent leaking, not licensed, externally regulated, or subject to environmental clean-up programs.  

          The people of New Mexico and various environmental and anti-nuclear groups are fighting for shut down of LANL’s nuclear production; however, it is likely that there are other dangerous facilities like this one.  Humans cannot control the forces of nature, and we must not ignore the dangers posed by the seismic activity of our planet.  It is impossible to predict when an earthquake or volcanic activity will take place with perfect accuracy.  It is possible to monitor seismic activity for the possibility of a major event, and avoid populating and building on areas with the likelihood of such an event; it is up to us to ensure this happens.   

For more information on Los Alamos, LANL, volcanoes, and earthquakes, please browse the list of links; they are all great resources.


Los Alamos National Laboratory:

Los Alamos Study Group
Independent watchdog group with information on LANL, nuclear weapons, and environmental concerns:  

Los Alamos Study Group article on plutonium pit production at LANL:  

El Dorado Sun Article on LANL plutonium pit production:  

United States Geological Survey site on U.S. volcanic activity:  

New Mexico Museum of Natural History Volcanoes Web Page:  

Volcano World
Excellent web site with information on volcanoes around the world:  

The Dynamic Earth @ Smithsonian Institution Museum of Natural History website:  

Photo Credits and URLs  

Mount St. Helen’s eruption
Volcano World
ok for educational use

Loma Prieta Earthquake Photo
"Loma Prieta Earthquake," Microsoft® Encarta® Encyclopedia. © 1993-2004 Microsoft Corporation. All rights reserved.
ok for educational use with above all rights reserved notation  

Valles Caldera Landsat Photo
Santa Fe New Mexico Library
ok for educational use

Los Alamos Area Satellite Image
National Geographic News
ok for educational use