4 PHOTOS Rock formations See Gallery Scientists study balanced rocks in active earthquake areas that have not toppled A precariously balanced rock near Searchlight, Nev. Fragile features such as this are easily toppled by shaking from strong earthquakes. Similar formations near California’s San Andreas Fault provide critical insights into the shaking and rupture patterns of past earthquakes. (Photo by Nick Hinze/Nevada Bureau of Mines & Geology) Unnamed fragile rock stack in Grass Valley area in the San Bernardino Mountains in California. The rocks lie near the San Andreas Fault within one of the highest seismic-hazard areas in the United States. (Photo courtesy of Lisa Grant Ludwig) Unnamed fragile rock stack in Grass Valley area in the San Bernardino Mountains in California. The rocks lie near the San Andreas Fault within one of the highest seismic-hazard areas in the United States. (Photo courtesy of Lisa Grant Ludwig) Unnamed fragile rock stack in Grass Valley area in the San Bernardino Mountains in California. The rocks lie near the San Andreas Fault within one of the highest seismic-hazard areas in the United States. (Photo courtesy of Lisa Grant Ludwig) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

Most rock formations are interesting to see while driving by, but one type in particular has had scientists intrigued for years."Precariously balanced rocks" is what the research team calls these boulder stacks, which have somehow remained upright despite being in active earthquake areas in Southern California.In fact, many have been dated to be more than 10,000 years old After years of trying to figure out why some of these balanced rocks hadn't toppled over despite being within miles of major fault lines like San Andreas, they ultimately concluded that earthquake vibrations can jump.And they believe these gaps in ground shaking are likely due to an interaction between the San Andreas and San Jacinto faults.One method used to make this determination involved calculating the force needed to topple the structures which was done by physically pushing some (but not toppling) and modelling others.Based on this data, an earthquake as recent as 1857 should have produced enough ground tremor to dismantle some that were still recently intact, leading them to come up with the theory about fault jumping.