56o11' N, 160o47' E
                           May 19, 1993
                              Via GVN

     In July 1992, during observations from the aircraft over
Kliuchevskoi, it has been found by S.A. Fedotov that almost all the
cone, which was formed during 1984-1990, has subsided.  The
aerophotosurvey made on 4 April 1993 confirmed this and allowed
more precise estimation of the the scales of the current event.  In
April 1993, the newly-formed crater at the summit of the volcano
had a diameter of 500 m and a depth of 200 m.  Failures of such a
scale are quite seldom events at Kliuchevskoi.  The last case like
this took place during 1962-1968.  A small new volcanic cone was
found on the floor of the formed crater.  A slight lava fountaining
was observed from its vent.
     In the middle of March 1993, after a short period of repose,
the activity of the volcano increased. Explosions occurred in the
central crater, the ash-gas cloud rose 1-2 km above the summit.  On
15 March, volcanic tremor appeared, from 15 April its amplitude
started to increase, reaching its maximum value of 2.4 microns
(vertical component 13 km) in the first decade of May.  At the
present time the amplitude of tremor is decreased.  Tremor at
Kliuchevskoi is noticed very often and is related, as usual, to the
eruptive activity of the summit crater and to a lesser degree to
flank eruptions.  The amplitude of tremor is largely dependent on
the style of volcanic activity: amplitude smaller than 0.5 microns
is associated with steam-gas emission; 0.5-3 microns with Vulcanian
explosions; more than 3 microns with Strombolian explosions or lava
spouting.  We suppose that the appearing and increase in volcanic
tremor indicate that the volcanic eruption is still slight and the
pressure in the magma feeding system of the volcano is increasing.
     Information contacts: V.V. Ivanov and V.N. Dvigalo. Institute
of Volcanology, Petropavlovsk-Kamchatskii, 683006, Russia.