Time Critical Studies | News: Ridge 2000 researchers discover/document seafloor eruption

Background Information

A new eruption on the East Pacific Rise (EPR) was first suspected during a visit to the site by the R/V Knorr in April, 2006. The Knorr deployed 12 new Ocean Bottom Seismometers (OBS), as a part of a continuing microseismicity monitoring project being led by Maya Tolstoy and Felix Waldhauser. The Knorr team then attempted to recover the 12 OBSs that had been previously deployed at the site. Only four OBS were recovered. Five other OBSs did not reply to the acoustic command sent from the ship and three others replied, but failed to return to the surface. Water column measurements were also made by the Knorr, yielding light-scattering measurements indicative of extensive particulates in the water column corroborating the evidence for a recent eruption.

Two follow-up cruises to the EPR site on the R/V New Horizon in April/May, 2006 and the R/V Atlantis in June, 2006 confirmed that a new eruption had, indeed, occurred on the seafloor. These multidisciplinary cruises worked to assess the extent of the new eruption and its effect on the biological communities, ecosystems, and chemistry at the EPR ISS. For more information on the response cruises and their findings, please visit the cruise updates webpage.

Maps & Seafloor Images at Eruption Site

Click the images below for large-scale high-resolution versions.

	Figure 1. Location map showing the EPR ISS.
	Figure 2. Close-up map of the EPR ISS showing the bulls eye where experiments are co-located. Courtesy of Suzanne Carbotte, Lamont-Doherty Earth Observatory.
	Figure 3. Map showing the locations of the OBSs from the Tolstoy/Waldhauser experiment at the ISS and their status. Figure from Carbotte, S. and D. Fornari, Focus on: Studies at the East Pacific Rise, Ridge Events Newsletter, Spring 2006.
	Figure 4. Seafloor photo from the Towcam taken during the April/May, 2006 R/V New Horizon cruise. Photo shows the new lava flow (darker and glassy) overlying an older flow (lighter). Courtesy of Dan Fornari, Woods Hole Oceanographic Institution; Jim Cowen, U. of Hawaii, and the TCS06NH science party.
	Figure 5. Seafloor photo from the Towcam taken during the June, 2006 R/V Atlantis cruise showing an OBS that has been stuck in the new lava flow. Courtesy of Dan Fornari, Woods Hole Oceanographic Institution and Maya Tolstoy, Lamont-Doherty Earth Observatory.

3-D Visualization

This file is a combination of several different data sets in one 3-D scene created with Fledermaus software. The scene can be downloaded and viewed using the free viewer program, iView3D. You can download iView3D here: http://www.ivs3d.com/download/iview3d_download.html.

The background is a bathymetry file showing the topography of the seafloor at the East Pacific Rise (EPR) from 8° to 10° North (latitude). This data comes from the Ridge Data Management System ( http://www.marine-geo.org/ridge2000/). At the northern part of the ridge, centered at 9°50' N, is the EPR ISS bulls eye. The bulls eye is a location chosen by the Ridge scientific community for the co-location of a series of different experiments, and there are several different data sets shown there including:

2 High-resolution bathymetry files showing more detailed seafloor features. (Courtesy of S. Soule, and V. Ferrini, Woods Hole Oceanographic Institution).
Hydrothermal vent locations shown as dark red pyramids (from the Ridge Data Management System).
Recovered OBSs shown as blue cylinders; stuck, replying OBSs shown as yellow cylinders; and stuck, unresponsive OBSs shown as red cylinders (Courtesy of M. Tolstoy, Lamont-Doherty Earth Observatory).
Light-scattering in the water column (MAPR) shown on the colored, above seafloor section (Courtesy of E. Baker, NOAA).
Seismic reflection line below the seafloor showing the structure of the magma chamber beneath the hydrothermal vent fields (Courtesy of G. Kent, Scripps Institution of Oceanography).