Scientists are hoping a recent project that involved explosions set off along California's largest earthquake fault will help protect people against the next big earthquake.A few days after the earthquake and tsunami in Japan, a team of researchers descended on the California desert for new insight into the next "big one.""I would expect significant damage within the city limits of San Diego," said geologist Pat Abbott.Abbott said it's when, not if, a 7.8-magnitude quake will strike the southern San Andreas Fault, and he's not the only one worried."We're pretty worried about it," said Gary Fuis, a geophysicist with the U.S. Geological Survey.Fuis and other leading experts went to areas near the Imperial and Coachella valleys that were close to faults and areas that were not as close, including an area from the Imperial County border west past Potrero.At those sites, they planted more than 120 explosives more than 60 feet deep, and detonated them. Seismic waves struck the fault areas, and experts said the change in the wave patterns can be measured by 3,000 different sensors."What this program is trying to do is get a 3D look at the faults," said Abbott.The program is giving an unprecedented look at hidden faults and the true contours of the San Andreas Fault and other faults in the Southern California area."It will help us better understand how bad it's going to shake down there when there's a big earthquake," said Joann Stock of Caltech, who is also part of the Salton Seismic Imaging Project.With the explosion tests finished, researchers have started analyzing the numbers, with some findings due out in September.The results could have major implications for local emergency plans and building standards, as scientists get a closer look at the danger below.The explosions were not large enough to create earthquakes along the faults, experts said.The Salton Seismic Imaging Project is funded with a $1.2 million grant from the National Science Foundation, with additional money from the USGS.