Smithsonian Institution
Global Volcanism Network Bulletin v. 20, no. 8, August 1995

Fernandina (Galapagos)  Now-cooling lava and the eruption's impact
       on plants and animals

Fernandina
Galapagos Islands, Ecuador
0.37 S, 91.55 W; summit elev. 1,495 m

Godfrey Merlen was granted permission by the Galapagos National
Park Service to make a post-eruption visit to Fernandina. The
recent eruption ceased on about 8 April 1995 (Bulletin v. 20, no.
5). Merlen looked at the eruptions impact on plants and animals,
and viewed the newly formed lava fields and cone in the absence of
the acrid gases and heat present during the eruption.

Merlin arrived at Cape Hammond on 26 July (figure 2) and climbed
for 2 hours along a well-known route to the kipuka adjacent the
cone. From this point, he approached the cone itself. He noted
Jasminocereus cactus, which form a distinctive part of the flora in
the area, and, which were partially scalded within several hundred
meters of the lava. Surprisingly, they were heavy with fruit.

The cone was approached from the SW. Large blocks of new lava
formed the base of the cone, and below them the old lavas were
totally covered with a scoria layer. Poking through this layer were
a number of Opuntia cactus. Many had been badly burnt by the heat,
but they had undergone strong regrowth, and some had up to 9 or 10
new pads. A few flowers were also present

He ascended the cone (figure 2) easily, due to its firm surface
composed of congealed spatter. From the rim he observed that the
lava lake had drained, leaving a reddish rubble in the bottom of
the crater. A visible entrance to a lava tunnel on the crater's W
side probably served as a lava exit route. Circumferential fissures
had developed in many areas around the rim, leading to inward
collapses. On the N side of the cone's rim, hot spots disclosed by
shimmering, heated air indicated that they were still too hot to
approach closely.

From the rim one could look upslope and see the earliest flows from
the eruption (figure 2). Though previously obscured by gases, it
now seems clear that the flow farthest to the N was of significant
extent, even though previously unseen. It had travelled a
considerable distance past the cone and then turned N, filling in
a low area well down toward the coast. Later, lava from the cone
butted up against this flow, making a continuous field of new lava.

In descending from the cone's N side towards the "Iguana Hill"
kipuka (figure 2), he crossed over the fresh new aa lava, but there
were also some smooth patches and many small lava tubes on the
surface. The track of the main lava tube could be followed by
noting the white encrustations on the rocks. On approach to these
encrustations extreme heat was felt. He assumed that a short
distance below the surface there were partially liquid lavas that
were still degassing. Away from these encrustations the surface of
the lava was quite cool.

Although Iguana Hill was wreathed in acidic volcanic gases for many
weeks during the eruption, Land Iguanas trapped there survived and
four adults were seen. This hardly represents all the iguanas, as
the dense scrub vegetation impeded investigation. Many of the
plants on the Iguana Hill kipuka were putting out leaves.
Zanthoxylum, Croton, and Cordia were all in full leaf, the former
were a particularly noticeable bright green.

Blue "smoke" was still visible a little to the NE of Iguana Hill.
There was also a little smoke in the low area behind the shoreline.
The coast itself was volcanically quiet. Heavy southerly swells
broke along a long, black beach that stood in front of the
near-vertical sea cliff. This eruption changed conditions at the
Cape Hammond landing little, if at all. Flightless cormorants were
building nests and some had eggs. The pupping season for the fur
seals and sea lion had begun.

A perspective sketch (figure 3) from a point several kilometers
offshore shows that the lava flow that started high on the shoulder
of the volcano lined up with the westernmost string of cones,
including one cone on the coast. However, the new cone, the vent
for much of this recently erupted lava, lies off this line to the
S.

Information Contacts: Godfrey Merlen, skipper of motor vessel
"Ratty," Fundacion Charles Darwin Para Las Islas Galapagos,
Estacion Cientifica Charles Darwin, Ecuador.

Figure 2. Sketch map showing newly recognized lava flows and the
location of kipukas, including the one termed "Iguana Hill" (IH).
Scale is approximate.

Figure 3.Sketch of Fernandina drawn from a point several
kilometers offshore looking NE. The sketch shows the alignment of
cones and some of the upper lava flows.