detected by the hydrophones of the Hawaiian Institute of Geophysics Network
(Norris and Johnson 1969). The source of the seismic signal was localized near
28°48
0 S and 140°30
0 W in the southeasterly prolongation of the Austral islands.
Geologist Rockne Johnson, while sailing with his wife and four children on board a
yacht called the R.V. Havaiki, discovered the underwater edifice of the Macdonald
Volcano in 1969. The volcano was named after a famous volcanologist, Gordon A.
Macdonald, who was a professor at the University of Hawaii.
The Polynesian Seismic Network (Réseau Sismique Polynésien = RSP) of
Tahiti closely monitors the activity of the Macdonald volcano. Because of its
shallow depths of less than 50 m from the surface, it could become an emerged
island at any time. Since its discovery, the Macdonald seamount has been frequently visited and mapped, and its eruptions were even directly observed on two
occasions. During the visit of a French Navy-patrol boat ‘‘Enseigne de Vaisseau’’
(EV) HENRY on July 1983, a team of scuba divers explored the central part of the
summit plateau at an average depth of 40 m. They identified a fissure with fresh
walls and spatter cones made up of scoria-like lava. They observed a discoloration
spot located approximately 2 km east of the summit, oriented NNW-SSE and
about 700 m long. When the RV MELVILLE made further observations on
October 11, 1987, the sea’s surface was bubbling with rising steam and ash. The
explosion of large bubbles with a rising gas column, and the formation of large
green stains, was observed on the ocean’s surface (Talandier et al. 1988).
Diving on Macdonald Volcano
On January 19,1989, after a brief pause of two weeks, the Macdonald seamount
started to give off signs of activity that was monitored by the seismic network in
Tahiti. Then, after a quiet period of four days, the volcano started to erupt again
Fig. 9.9 Three-dimensional
view of Macdonald Seamount
in the Austral chain is shown.
The rift zones representing
lava channels show a star
shaped form going down
slope. A. Bonneville compiled
the bathymetry
320
9 Hotspots
(Norris and Johnson 1969). The source of the seismic signal was localized near
28°48
0 S and 140°30
0 W in the southeasterly prolongation of the Austral islands.
Geologist Rockne Johnson, while sailing with his wife and four children on board a
yacht called the R.V. Havaiki, discovered the underwater edifice of the Macdonald
Volcano in 1969. The volcano was named after a famous volcanologist, Gordon A.
Macdonald, who was a professor at the University of Hawaii.
The Polynesian Seismic Network (Réseau Sismique Polynésien = RSP) of
Tahiti closely monitors the activity of the Macdonald volcano. Because of its
shallow depths of less than 50 m from the surface, it could become an emerged
island at any time. Since its discovery, the Macdonald seamount has been frequently visited and mapped, and its eruptions were even directly observed on two
occasions. During the visit of a French Navy-patrol boat ‘‘Enseigne de Vaisseau’’
(EV) HENRY on July 1983, a team of scuba divers explored the central part of the
summit plateau at an average depth of 40 m. They identified a fissure with fresh
walls and spatter cones made up of scoria-like lava. They observed a discoloration
spot located approximately 2 km east of the summit, oriented NNW-SSE and
about 700 m long. When the RV MELVILLE made further observations on
October 11, 1987, the sea’s surface was bubbling with rising steam and ash. The
explosion of large bubbles with a rising gas column, and the formation of large
green stains, was observed on the ocean’s surface (Talandier et al. 1988).
Diving on Macdonald Volcano
On January 19,1989, after a brief pause of two weeks, the Macdonald seamount
started to give off signs of activity that was monitored by the seismic network in
Tahiti. Then, after a quiet period of four days, the volcano started to erupt again
Fig. 9.9 Three-dimensional
view of Macdonald Seamount
in the Austral chain is shown.
The rift zones representing
lava channels show a star
shaped form going down
slope. A. Bonneville compiled
the bathymetry
320
9 Hotspots