A magnitude 6.9 earthquake on San Diego’s Rose Canyon Fault could damage 100,000 residences, cause widespread road and bridge failures, and make parts of Mission Bay sink about a foot, according to the most detailed disaster scenario ever done on the region.

Such a temblor could also cut gas and water service between La Jolla and the Silver Strand for months, collapse key municipal buildings, and close the San Diego-Coronado Bridge, says a report by the San Diego chapter of the Earthquake Engineering Research Institute. Parts of the fault would rupture the Earth’s surface and shift the landscape 6 to 7 feet, damaging streets so badly it would make it hard for police, firefighters and paramedics to get around.