All earthquakes are recorded in Coordinated Universal Time (UTC). This is the modern equivalent of Greenwich Mean Time. To determine the local time that an earthquake occurred, use the following tables to subtract the appropriate number of hours from the UTC time to your time zone.

Winter (Standard) Time Zones - last Sunday in October to first Sunday in April
Pacific Standard Time	Mountain Standard Time	Central Standard Time	Eastern Standard Time	Atlantic Standard Time	Newfoundland Standard Time
UTC - 8 hours	UTC - 7 hours	UTC - 6 hours	UTC - 5 hours	UTC - 4 hours	UTC - 3 hours 30min
An earthquake occurring at 12:00 UTC would be at the following local times:
04:00 PST	05:00 MST	06:00 CST	07:00 EST	08:00 AST	08:30 NST

Summer (Daylight Savings) Time Zones - first Sunday in April to last Sunday in October
Pacific Daylight Time	Mountain Daylight Time	Central Daylight Time	Eastern Daylight Time	Atlantic Daylight Time	Newfoundland Daylight Time
UTC - 7 hours	UTC - 6 hours	UTC - 5 hours	UTC - 4 hours	UTC - 3 hours	UTC - 2 hours 30min
An earthquake occurring at 12:00 UTC would be at the following local times:
05:00 PDT	06:00 MDT	07:00 CDT	08:00 EDT	09:00 ADT	09:30 NDT