3D electrical resistivity imaging of the near-surface structure of mud-volcano vents

• Published in: Tectonophysics Vol. 509; no. 3; pp. 181 - 190
• Main Authors: Zeyen, Hermann, Pessel, Marc, Ledésert, Béatrice, Hébert, Ronan, Bartier, Danièle, Sabin, Mikaël, Lallemant, Siegfried
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-08-2011; Elsevier
• Subjects: Conduits; Earth Sciences; Electrical resistivity; Faults; Hikurangi accretionary prism; Low temperature resistance; Mud; Mud volcano; New Zealand; Resistivity; Sciences of the Universe; Three dimensional; Tomography; Vents; PSE, New Zealand; New Zealand; Tomography; Hikurangi accretionary prism; Mud volcano; Resistivity
• ISSN: 0040-1951; 1879-3266
• DOI: 10.1016/j.tecto.2011.05.007

A near-surface study of the 3D electrical resistivity distribution of a cold mud volcano field in New Zealand is presented. Inversion of 16 densely spaced profiles allowed to image the uppermost 25–30
m. The mud distribution is characterized by areas of very low resistivity (less than 7
Ωm) embedded in river terrace sediments with resistivities of above 30
Ωm. Within the first 4–6
m below the surface, a good correlation between mud vents and low electrical resistivities is observed. Between ca. 5 and 15
m depth, in contrast, the mud distribution does not reflect anymore the distribution of surface vents but is restrained to a few pipe-like structures that link a deeper mud reservoir to the vents at the surface. The obtained resistivity distribution allows also locating the Masterton strike-slip fault just north of the mud volcano field, confirming the role of this fault as conduit of the mud from deeper layers to the surface.
► 3D resistivity image of a mud-volcano system ► Complicated mud circuits near the surface ► Masterton strike-slip fault limits distribution of mud