In article , "Rev.RP Jones"
writes:

Subject: Rumble on the water
From: "Rev.RP Jones"
Date: Fri, 16 Jul 2004 05:39:06 GMT

Im just been fishing on City Island, was a big rumble on the water.
Scared me half to death !
No reports of anything ?

-Rev

- Possibly tiny earthquake ( if local) due to " Isostatic rebound";
The last glaciation put abouot a Mile of ice above NYC;
( 64.425 lbs per sq foot * ~ 5,000 feet = Muco Pressure downwards..
- so this compressed the rock, which deforms slightly.
Ice melts..
- with no Ice pressing it down the Rock moves up a tich now and again...
& you get a small ( or medium sized) rumble
My best guess

( & what iffen you're underwater when this all happens ??)

Dan