Earthquakes are our big issue.
Continuous gas delivery is very debatable then.
A lot of the gas pumping stations use electric pumps, so a widespread power outage may affect the availability of natural gas as well. IIRC, during the rolling blackouts in Texas last winter, there were a couple of isolated areas in New Mexico that couldn't get gas for heating their homes due to inadequate pumping capability on some of the gas transmission pipelines.