Topographic features of rift zones of the seamounts on the Pacific Plate
Abstract
Several volcanos on land have rift zones that extend outward from the summits. A rift zone is an elongated topography made by intrusion or extrusion of magma. A volcano usually has two or three rift zones. Several studies indicated that the angle between rift zones is about 120° (e.g., Wentworth and Macdonald, 1953; Carracedo, 1994). In general, small-sized seamounts (< 1 to 600 km3) in the eastern Pacific Ocean are highly diverse in shape (Batiza and Vanko, 1983). Most of the small-size seamounts do not have any rift zones or have immature rift zones. On the other hand, rift zones with a length of more than 100 km could found on large volcanic islands such as Hawaii Island (Dieterich, 1998). Vogt and Smoot (1984) studied the Japanese Seamounts, which sizes are between the small seamounts described by Batiza and Vanko (1983) to the larger guyots (104 to 105 km3) as Hawaii-Emperor Seamount chain. The age of the Japanese Seamounts is 94 Ma to 102 Ma. Vogt and Smoot (1984) pointed out that several seamounts of the Japanese Seamounts have more than three rift zones. We examined the rift zones of seamounts on the Pacific Plate except for Japanese Seamounts: Seamounts of the Hawaiian Ridge, seamounts south of the Mid-Pacific Mountains, seamounts in the eastern part of the Marcus-Wake Seamounts, seamounts of the Tokelau Seamounts, Seamounts near the Mariana Trench. The ages of seamount except Hawaiian Ridge are close to the Japanese seamounts. We examined the topographic features of the seamounts and identified rift zones using multibeam data.
The lengths of the rift zones of the studied seamounts are proportional to the size of the seamount. The length of the rift zone in Seamounts of the Hawaiian Ridge with a diameter of 7667 km extends to 36 km. Most of the studied seamounts have three to six rift zones. Our results are consistent with those by Vogt and Smoot (1984). Thus, we concluded that most of the seamounts on the Pacific Plate might have the rift zones which topographic feature is similar to that of the seamount studied in Vogt and Smoot (1984). Our study also suggests that the number of rift zones in the seamounts of the Hawaiian Ridge may increase with age. The correlation between the number of rift zones and ages of seamounts may be attributed to the difference in the rate of the Pacific Plate movement or the activity of the Hawaiian hotspot.- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMV040.0022F
- Keywords:
-
- 8419 Volcano monitoring;
- VOLCANOLOGY;
- 8427 Subaqueous volcanism;
- VOLCANOLOGY;
- 8439 Physics and chemistry of magma bodies;
- VOLCANOLOGY;
- 8494 Instruments and techniques;
- VOLCANOLOGY