These photos show light sweet oil seeping to the surface along the Citalopa River. When digging at the riverbank, oil will enter the hole. The seep is the result of a fault that did not completely seal. The fault crosses perpendicular to the river's course. Under the riverbed the pressure of the river's water holds the oil below the surface. Over time the reservoir pressure builds up and overcomes the weight of the river's water. According to residents of the area, when this happens, the river flows oil from bank to bank for miles. This is in a remote part of the country, and no documentation exists to corroborate the frequency of its occurrance, but it is known to occur in other parts of the world, as well.