Notes on Vent Field Description:
Monowai (= Orion) Seamount, southern Tofua Arc (STA); Global Volcanism Program 242050 Monowai Seamount includes both cone and caldera as single database listing; however, here we are listing Monowai Caldera and Monowai Cone separately, based on Leybourne et al. (2012): "Hydrothermal plume mapping has shown at least three major hydrothermal systems associated with the caldera and cone: (1) the summit of the cone, (2) low-temperature venting (<60°C; Mussel Ridge) on the southwestern wall of the caldera, and (3) a deeper caldera source with higher temperature venting that has yet to be observed... We believe the Monowai volcanic center is host to a robust magmatic-hydrothermal system, with significant differences in the style and composition of venting at the cone and caldera sites."; Monowai Cone is just south of Monowai Caldera; Graham et al. "signs of recent eruptive and current hydrothermal activity"; 2004 plume only: "As the Tangaroa passed over the top of the cone, plumes of bubbles rising off the summit at a depth of ~150 meters (~500 feet) were recorded on the ship's echo sounder and several sulfur slicks were observed on the sea surface above the summit." (http://oceanexplorer.noaa.gov/explorations/05fire/logs/april05/april05.html)
Year and How Discovered (if active, visual confirmation is listed first):
1998 R/V Sonne SO-135; 2004 plume only
Discovery References (text):
Stoffers, P., et al. (1999) Cruise report Sonne 135, Havre Trough-Taupo Volcanic Zone: Tectonic, magmatic and hydrothermal processes, Sept. 9 - Oct. 15, 1998: Berichte-Reports, Institut für Geowissenschaften, Universität Kiel, v. Nr. 1, p. 77.
Other References (text):
New Zealand American Submarine Ring of Fire 2005 Kermadec Arc Submarine Volcanoes, NOAA VENTS Cruise Report compiled by Merle, Embley and Chadwick
Graham et al. (2008) Structure and petrology of newly discovered volcanic centers in the northern Kermadec-southern Tofua arc, South Pacific Ocean. JGR 113(B8): B08S02.1-B08S02.24
Wright, I. C., et al. (2008) Collapse and reconstruction of Monowai submarine volcano, Kermadec arc, 1998–2004, J. Geophys. Res., 113, B08S03, doi:10.1029/2007JB005138.
Leybourne et al. (2012) Submarine Magmatic-Hydrothermal Systems at the Monowai Volcanic Center, Kermadec Arc. Economic Geology, 107, 1669-1694, doi:10.2113/econgeo.107.8.1669.