Seamount formation structure of the Tofua Arc 12 in the Lau basin: Constraints based on bathymetry and magnetic modeling

Abstract

We examined the seamount formation structures of Tofua Arc (TA) 12 in the South West Pacific by applying magnetization vector inversion (MVI) modeling to determine the structure of submarine hydrothermal deposits using bathymetric and magnetic data. Our model revealed that while ascending from deep to shallow layers, a strong concentration of magnetic susceptibility shifts from the surrounding slopes of the seamount to the caldera rim summits and directly under the caldera depression. The strong magnetic susceptibility estimated in the model correlated with the first eruption-forming seamounts and additional magma intrusion (second eruption) of the magnetic material displaced from the surrounding slope. The low magnetic susceptibility near the seafloor within this study area supports hydrothermal alteration around the inner ring fault created by the occurrence of landslides inside the caldera. Our study revealed the formation structure and the three-stage formation process of the TA 12 seamount.

Data Source Description

bathymetry : ta12-seadepm(utm)_resize_surfv6byOM.xyz

Geomagnetic Intensity : ta12-totallevel(utm)_resize_surfv6byOM.xyz

Total Magnetic Intensicy : ta12-anolevel(utm)_resize_surfv6byOM.xyz

Analytic Singal : ta12-anal(utm)_resize_surfv6byOM.xyz

Reduce to the Pole : ta12-rtp(utm)_resize_surfv6byOM.xyz

3D Magnetization Vector Inversion : MVI_Zadd_2019_03_09_02_02_31.xyz