Over 200 million years of geological activity has given Big Sur some of the most complex geology in California. The area is built from a diverse assortment of rocks, called the Franciscan Complex. This complex occurs throughout California’s coastal mountain ranges, and is the result of plate tectonics bringing ancient rocks from hundreds, if not thousands, of miles away and changing their shape. These rocks are usually undersea sediments, volcanic rocks, and rocks that have been transformed, or metamorphosed, through heat and pressure. These rocks can be found in the park underneath Pfeiffer Falls, in the Big Sur River Gorge, along the Pine Ridge trail and as pebbles in the Big Sur River. Big Sur is still incredibly geologically active. The dramatic landscape that many people come to see - the Santa Lucia Mountains, the rugged coastline, and the deep canyons - is the result of ongoing geological processes. You may even feel an earthquake from the active Hosgri-Gregorio fault that runs through the park.