close but no...
320.0 db's , TAMBORA INDONESIA ERUPTION,1815, EJECTED 36 CUBIC MILES.APPROXIMATELY EQUAL TO
14,000 MEGATON NUCLEAR BOMBS OR A 14 GIGATON BOMB BASED ON EJECTED VOLUME,CHANGE IN MEGATONS TIMES 1.345 EQUALS VOLUME EJECTED CHANGE.IF WAS A NUCLEAR BOMB IT WOULD CREATE A CRATER ABOUT 12.4 MILES WIDE AND 1.33 MILES DEEP.INTERNAL PRESSURE IS BELIEVED TO BE ABOUT 47 MILLION P.S.I. = 347 DB