Date: Thu, 23 Feb 1995 13:26:11 MST
From: Rick Wunderman--Global Volcanism Network
Subject: Galapagos eruption (Fernandina)
Fernandina
Galapagos Islands, Ecuador
0.37xS, 91.55xW; summit elev. 1,495 m
All times are local (= GMT - 6 hours).
Fernandina volcano, which forms the westernmost island of the
Galapagos archipelago, produced a red glow that was seen by
both mariners and geologists on the evening of 25 January.
Inspection revealed lava erupting from a fissure on the island's
SW flank and thought to be coming from older, but unvegitated
cones that extend in a line from the coast. The venting fissure
was located about 5 km from the coast near Cape Hammond
and the flow extended all the way to the sea, entering at a point
about 3 km N of the Cape. Lava constructed a delta, and
although reports documented a shift in the character of activity,
suggesting decrease after 13 January, the eruption continued as
of mid-February. More information will appear in the full
Bulletin report.
>From the morning of 27 January a group of interested observers
(Godfrey Merlin, David Day, Rolf Siever, Fernando Rivera,
Deana Reirer, Jim Stimic, and two Isabella Park Guards) sailing
on the "Ratty" made detailed observations of the eruption from
land and sea.
As they approached from the S on the morning of the 27th, they
observed two distinct plumes, the largest being more to the W.
These plumes coalesced into a single plume, rising 3-4 km and
being transported to the W at that height." The two separate
plumes came from gases rising from the fissure vent and from
lava entering the sea.
Concerning the eruption itself, Godfrey Merlen, reported the
following on 3 February.
"Although some new lava fields have been created, the eruption
has settled into a pattern with fountaining lava (30-200 m [tall])
forming scoria ridges alongside its fissure. It seems that in the
first moments the fissure opened up over [a distance of] about
1.5 km but later became restricted to about 400 m (29 January).
However, a film taken on 2 February, seems to show an
increase in the length of the fissure erupting. A river of lava
about 100 m wide is flowing to the sea, about 5 km away, where
new land is slowly being formed. The front entering the sea is
about 800-m long."
The eruption followed a Mb 5.1 earthquake at 1811 on 14
December (0011 GMT on 15 December) approximately under
the summit of Darwin volcano, on Isabela. Locations are
inaccurate, however, and could be off by as much as 100 km.
An additional five earthquakes over M 4.4 also took place, with
calculated hypocenters farther N, including one on 11 January
(Mb 5.1, Msz 4.9) with a calculated hypocenter about 20 km N
of Pinta.
Although the eruption has yet to be imaged from space, and the
NASA TOMS (total ozone mapping spectrometer) is currently
inoperative, the eruption has been documented on film by local
and visiting scientists, and by a visiting TV crew from public
television in Japan. The TV crew's producer, Hiromichi
Iwasaki, described a 1.5-km radius of discolored water around
the entry, and rain due to condensed steam.
Tui De Roy reported that the abundance of dead fish floating
on the surface attracted seabirds who dove into the heated
waters and were scalded to death. She also reported that some
land animals seemed unable to sense the danger from heated
surfaces and in not fleeing the hot lava they were burned to
death. No Galapagos tortoises currently inhabit Fernandina
Island.
Fernandina also erupted in 1991, 1988, 1984, 1981 and 17 to 18
other times in a historical record going back as far as 1813.
Most of the documented eruptions lasted less than a year and
vented from the central summit caldera.
Information Contacts: Godfrey Merlin, Skipper of M.V. "Ratty,"
Fundacion Charles Darwin Para Las Islas Galapagos, Estacion
Cientifica Charles Darwin; Jim Stimic, Los Alamos National
Laboratory, EES 1, Geology-Geochemistry, Los Alamos, NM,
87545 USA; National Earthquake Information Center, MS 967,
Denver Federal Center, Box 25046, Denver, CO 80225 USA;
Hiromichi Iwasaki, Producer, Science Programmes Division,
Japan Broadcasting Corporation, Jinnan, Shibuya-ku, Tokyo,
Japan; Tui De Roy, former Galapagos resident and journalist-
photographer (telephone/fax in New Zealand: 64 3 525 8370).
++ Global Volcanism Network
++ Smithsonian Institution
++ NMNH, MRC 129, Washington DC 20560 USA
++ Phone: (202) 357-1511 Fax: (202) 357-2476
++ Internet: mnhms017@sivm.si.edu Bitnet: mnhms047@sivm
Rick Wunderman, Global Volcanism Network, MRC 129, NHB,
Smithsonian Institution, Washington, DC 20560