Seismic Monitor displays the time each map was made in the lower right hand corner.
UTC time is used.

What is UTC Time?

Nearly all international time is kept using Coordinated Universal Time (UTC) and a twenty four hour clock. UTC is also known as GMT, or Greenwich Mean Time.

Here is a conversion table to help convert UTC to your own local time zone.

Timezones
Relative
GMT
Common
abbreviation
Name Alternative
Name(s)
Daylight Savings
Time (DST)
-12 (west) IDLW International Date Line West    
-11 (west) NT Nome Time    
-10 (west) AHST Alaska-Hawaii Standard Time CAT (Central Alaska Time)
HST (Hawaii Standard Time)
HDT (Hawaii Daylight Time)
-09 (west) YST Yukon Standard Time   YDT (Yukon Daylight Time)
-08 (west) PST Pacific Standard Time   PDT (Pacific Daylight Time)
-07 (west) MST Mountain Standard Time   MDT (Mountain Daylight Time)
-06 (west) CST Central Standard Time   CDT (Central Daylight Time)
-05 (west) EST Eastern Standard Time   EDT (Eastern Daylight Time)
-04 (west) AST Atlantic Standard Time   ADT (Atlantic Daylight Time)
-03 (west)        
-02 (west) AT Azores Time    
-01 (west) WAT West Africa Time    
±00 GMT Greenwich Mean Time UT (Universal Time)
UTC (Coordinated Universal Time)
WET (Western European Time)
BST (British Summer Time)
+01 (east) CET Central European Time FWT (French Winter Time)
MET (Middle European Time)
MEWT (Middle European Winter Time)
SWT (Swedish Winter Time)
MEST (Middle European Summer Time)
MESZ (Middle European Summer Time)
SST (Swedish Summer Time)
FST (French Summer Time)
+02 (east) EET Eastern European Time and
USSR Zone 1
   
+03 (east) BT Baghdad Time and
USSR Zone 2
   
+04 (east) ZP4 USSR Zone 3    
+05 (east) ZP5 USSR Zone 4    
+06 (east) ZP6 USSR Zone 5    
+07 (east) ZP7 USSR Zone 6    
+08 (east) WAST West Australian Standard Time and USSR Zone 7 CCT (China Coast Time) WADT (West Australian Daylight Time)
+09 (east) JST Japan Standard Time and
USSR Zone 8
   
+09.5 (east) ACT Australian Central Time    
+10 (east) EAST East Australian Standard Time and
USSR Zone 9
GST (Guam Standard Time) EADT (East Australian Daylight Time)
+11 (east)        
+12 (east) IDLE International Date Line East NZST (New Zealand Standard Time)
NZT (New Zealand Time)
NZDT (New Zealand Daylight Time)
A more complete listing of time zone abbreviations is here.