Malumalu (also known as Malu Malu, Malumalu Seamount), is a volcanic
seamount in
American Samoa. Together with
Savaii,
Upolu and
Tutuila, it forms a topographic structure close to the
Tonga Trench, which lies about 100 kilometres (62 mi) south.[1] Malumalu lies about 66 kilometres (41 mi) south of
Ofu island[2] and is also known as "Southeast Bank".[3] It is about 25 kilometres (16 mi) wide at its base and is part of the Mula ridge, which extends to Tutuila.[4]
The seamount is a young volcano at the eastern end of a lineament that begins on Tutuila.[5] This lineament has been named the "Malu trend" (in contrast to the "Vai trend" farther northeast, which runs between Ofu,
Ta'u and
Vailulu'u).[6] This is comparable to the "Kea" and "Loa" trends in
Hawaii.[7] Malumalu is not much older than Vailulu'u,[8] which has erupted in historical time.[1]Actinideisotope ratios indicate the occurrence of at least three volcanic events in the last 300,000 years, including at least two in the last 150,000 years and at least one in the last 8,000 years.[9] According to one model of the behaviour of the
Samoa hotspot, volcanic activity at Malumalu will decline in the next 10,000 - 100,000 years as the
mantle plume is pushed farther northeast to Vailulu'u by mantle flow generated by the Tonga
slab.[10]
^Wright, Dawn J.; Roberts, Jed T.; Fenner, Douglas; Smith, John R.; Koppers, Anthony A.P.; Naar, David F.; Hirsch, Emily R.; Clift, Leslie Whaylen; Hogrefe, Kyle R. (2012), "Seamounts, Ridges, and Reef Habitats of American Samoa", Seafloor Geomorphology as Benthic Habitat, Elsevier, p. 792,
doi:
10.1016/b978-0-12-385140-6.00058-x,
ISBN9780123851406
^Hart, Stanley R.; Staudigel, Hubert; Konter, Jasper; Jackson, Matthew G.; Russell, Jamie A.; Koppers, Anthony A. P. (1 June 2008). "Samoa reinstated as a primary hotspot trail". Geology. 36 (6): 437.
Bibcode:
2008Geo....36..435K.
doi:
10.1130/G24630A.1.
ISSN0091-7613.
Sims, Kenneth W. W.; Hart, S. R.; Reagan, M. K.; Blusztajn, J.; Staudigel, H.; Sohn, R. A.; Layne, G. D.; Ball, L. A.; Andrews, J. (April 2008). "238U-230Th-226Ra-210Pb-210Po, 232Th-228Ra, and 235U-231Pa constraints on the ages and petrogenesis of Vailulu'u and Malumalu Lavas, Samoa". Geochemistry, Geophysics, Geosystems. 9 (4): n/a.
Bibcode:
2008GGG.....9.4003S.
doi:
10.1029/2007GC001651.
hdl:1912/3263.
S2CID54637043.
Workman, R. K.; Hart, S. R.; Jackson, M.; Regelous, M.; Farley, K. A.; Blusztajn, J.; Kurz, M.; Staudigel, H. (April 2004). "Recycled metasomatized lithosphere as the origin of the Enriched Mantle II (EM2) end-member: Evidence from the Samoan Volcanic Chain". Geochemistry, Geophysics, Geosystems. 5 (4): n/a.
Bibcode:
2004GGG.....5.4008W.
doi:
10.1029/2003GC000623.
hdl:1912/462.
S2CID13987904.