Complex sentence: The origin of faulting was located five miles north of the San Fernando Valley and considerable damage was seen in localized portions of the valley and also in the foothills of the San Gabriel mountains above the fault block.
Split into simpler sentences: The origin of faulting was located five miles north of the San Fernando Valley. Considerable damage was seen in localized portions of the valley and also in the foothills of the San Gabriel mountains above the fault block.