Original Research ARTICLE
Structure of Lō'ihi Seamount, Hawai’i, and Lava Flow Morphology from High-resolution Mapping
- 1Monterey Bay Aquarium Research Institute (MBARI), United States
- 2Department of Biology, Western Washington University, United States
- 3University of Hawaii at Manoa, United States
- 4Woods Hole Oceanographic Institution, United States
High-resolution bathymetric data were collected using AUV Sentry at the summit and at two hydrothermal vent fields on the deep south rift of L¯o‘ihi Seamount. The summit map records a nested series of caldera and pit crater collapse events, uplift of one resurgent block, and eruptions that formed at least five low lava shields that shaped the summit. The earliest and largest caldera, formed ~5900 years ago, bounds almost the entire summit plateau. The resurgent block was uplifted slightly more than 100 m and has a tilted surface with a dip of about 6.5° towards the SE. The resurgent block was then modified by collapse of a pit crater centered in the block that formed West Pit. The shallowest point on L¯o‘ihi’s summit is 986 m deep and is located on the northwest edge of the resurgent block. Several collapse events culminated in formation of East Pit, and the final collapse formed Pele’s Pit in 1996. The nine mapped collapse and resurgent structures indicate the presence of a shallow crustal magma chamber, ranging from depths of ~1 km to perhaps 2.5 km below the summit, and demonstrate that shallow sub-caldera magma reservoirs exist during the late pre-shield stage. On the deep south rift zone are young medium- to high-flux lava flows that likely erupted in 1996 and drained the shallow crustal magma chamber to trigger the collapse that formed Pele’s Pit. These low hummocky and channelized flows had molten cores and now host the FeMO hydrothermal field. The Shinkai Deep hydrothermal site is located among steep-sided hummocky flows that formed during low-flux eruptions. The Shinkai Ridge is most likely a coherent landslide block that originated on the east flank of L¯o‘ihi.
Keywords: caldera, Pit crater, landslide, Channelized flow, Hummocky flows, Loihi Seamount
Received: 27 Aug 2018;
Accepted: 08 Mar 2019.
Edited by:Carles Soriano, Instituto de Ciencias de la Tierra Jaume Almera (ICTJA), Spain
Reviewed by:Alessandro Tibaldi, University of Milano-Bicocca, Italy
Sharon Allen, University of Tasmania, Australia
Copyright: © 2019 Clague, Paduan, Caress, Moyer, Glazer and Yoerger. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. David A. Clague, Monterey Bay Aquarium Research Institute (MBARI), Moss Landing, United States, email@example.com