As an emergency response general and manufactured home contractor having worked in the aftermath of every major earthquake since 1086 as well as floods, fires and even Hurricane Charley in Florida in '04 I can't tell you how important adding a few bolts to your foundation and some shear panel to your cripple wall will keep you in your home instead of in the street.
Are you asking if gas is more dangerous than electric lines? Yes they would be because the gas continues to flow until shut off.
To be a prepared person it is good to have a wrench set by the main cut-off. During the whole house inspection the inspector will show you where that is and how it works.