The Los Angeles Seismicity Experiment (LARSE) is a study of the effects of a series of small sub-surface explosions that will be detonated along a 60-mile line that runs from the Pacific Ocean across the San Fernando Valley, the San Gabriel Mountains and out into the Mojave Desert. The sound waves generated by these small blasts are enough to provide meaningful data to hundreds of portable seismometers, but are not strong enough to be felt by people or to trigger earthquakes. During these tests, vibrations called seismic waves radiate out from the small explosion. The speed of these waves depends on the type of rock they travel through, as well as the rock's temperature and pressure. When the waves arrive at distant seismographs, some will have been delayed, depending on the geologic features they've traveled through. The difference in travel time allows scientists to create a picture of the structure and composition of the earth's interior. This process, called tomography, creates a picture of the earth below which can be used to understand and predict the shifts in the earth's crust that cause earthquakes. LARSE is a collaboration between the Southern California Earthquake Center (SCEC), the United States Geological Survey (USGS), and many other organizations.
The drill bit is on the ground in the lower right-hand corner.
Alpha Explosives company was responsible for loading all the holes with the proper charge at the proper depth.

On the Road with the Faultline Project
©1999 Exploratorium