EarthRef.org Digital Archive (ERDA) -- DeepFreeze 2000 hydrocast data for Vailulu'u volcano -- SAM04

Description
The hydrothermal system of the Vailulu'u volcano that is located to the East of Ta'u island in the Samoan Islands has been investigated by measuring standard CTD and nephelometry onboard the US Coast Guard Polar Star. Vailulu'u marks the current location of the Samoan hotspot. This Microsoft Excel file contains the CTDN data in three Excel spreadsheets with useful plotting utilities to display the CTDN data at any scale. SAM04 is a single hydrocast inside the crater close to a topographic low in the crater floor in the SW part of the crater.

Location
14º 12.73' S

169º 03.44' W, Pacific Ocean, American Samoa, Vailulu'u Volcano, Rockne Seamount, Samoan Islands, Samoan Hotspot Trail

Instructions
The data are presented as Excel spreadsheets with useful plotting utilities to display the CTDN data at any scale. This display can be adjusted by checking the checkboxes in the legend, by choosing different parameters for plotting and by choosing the appropriate ranges on the axes. Click on the ¿redraw¿ button to refresh the chart. Each spreadsheet contains an ¿info¿ sheet with the basic parameters describing the CTDN casts and a table defining all the down, up and horizontal legs in the hydrocast. This sheet also contains a table defining all parameters (including there column number and label) that can be found in the ¿header¿ and ¿data¿ sheets. When opening the Microsoft Excel file be sure to ¿enable macros¿ in order to activate the Visual Basic plotting software.

Keywords
Underwater Volcano, Volcanic Crater, Hydrothermal System, Seamount, Hotspot, CTD, Nephelometry, SeaBIRD

Project -- Other Projects -- Vailulu'u: the Active Samoan Hotspot Volcano
Vailulu'u Seamount is identified as an active volcano marking the current location of the Samoan hotspot. This seamount is located 45 km east of Ta¿u Island, Samoa, at 169¿03.5¿W, 14¿12.9¿S. Vailulu'u defines the easternmost edge of the Samoan Swell, rising from 5000m ocean floor to a summit depth of 590m, and marked by a 400m deep and 2 km wide summit crater. Its broad western rift and stellate morphology brand it as a juvenile progeny of Ta¿u. Seven dredges, ranging from the summit to the SE Rift zone at 4200m, recovered only alkali basalts and picrites. Isotopically, the volcano is strongly EM2 in character and clearly of Samoan pedigree (87Sr/86Sr: 0.7052-0.7067; 143Nd/144Nd: 0.51267-0.51277; 206Pb/204Pb: 19.19-19.40). 210Po-210Pb data on two summit basalts indicate ages younger than 50 years; all of the recovered rocks are extremely fresh, and veneered with glass. An earthquake swarm in early 1995 may attest to a recent eruption cycle.