There is a complex interaction
between earthquakes and
volcanic eruptions. Currently,
swarms of small earthquakes can
be used to predict the possibility
of a major eruption. In general,
earthquake prediction is very
difficult. Good news here - no
volcanic threats in Israel. The
various Syrian volcanos - Jabal ad
Druze, Es Safa and the Mt. Avital
complex in the Golan Heights - do
not currently pose a danger.  The
Aegean Arc island of Santorini
had a massive  explosion in 1638
BC and has been active. Some of
the earliest regional art and
pottery depicts eruptions of
Hasan Dagi. For the moment,
we'll assume nothing like Toba,
Tomba or Krakatoa will impact
Israel in the immediate future.
There are no appreciable tides at
the ports of Haifa or Eilat.     
We note that Jabal al Tair at the southern end of the Red Sea had been dormant
for over 120 years. After several weeks of many minor earthquakes, it erupted
in December 2007 (and is still active) killing six Yemeni sailors and forcing the
evacuation of dozens more. By a  miracle, NATO warships rescued two sailors
who had been drifting in the shark-infested waters for 20 hours.