The launch of a new GVP website is scheduled for Monday, May 20, 2013.
|
A photograph is not available for this volcano. |
Subregion Name: | Austral Islands | |
| Volcano Number: | 1303-06- | ||
| Volcano Type: | Submarine volcano | ||
| Volcano Status: | Historical | ||
| Last Known Eruption: | 1989 | ||
| Summit Elevation: | -39 m | - 128 feet | |
| Latitude: | 28.98°S | 28°59'0"S | |
| Longitude: | 140.25°W | 140°15'0"W | |
| Discovered by the detection of teleseismic waves in 1967, Macdonald seamount (also known as Tamarii seamount) rises from a depth of about 1800 m to within 27 m of the sea surface at the eastern end of the Austral Islands. The alkali-basaltic submarine volcano marks the site of a hotspot that was the source of the Austral-Cook island chain. The summit of the seamount, named after volcanologist Gordon Macdonald, consists of a flat plateau about 100 x 150 m wide with an average depth of about 40 m. The summit plateau is capped with spatter cones that form steep-sided pinnacles. Most eruptions of Macdonald have been seismically detected, but in 1987 and 1989 pumice emission was observed from research vessels. Pumice rafts observed in the South Pacific in 1928 and 1936 may also have originated from Macdonald seamount. | |||