What is an Earthquake shut off valve? An earthquake valve is a device that automatically shuts off the gas flow to a building in the case of seismic activity. For more information, visit our Gas Shutoff Devices page. Was this helpful? Related articles Does PG&E Install an Earthquake shut off valve? What do I do if my earthquake shut off valve tripped? I have a water leak; how do I turn off my electricity? What should I do if someone gets an electric shock? Does PG&E offer safety check or a pilot relight for sub-metered tenants?