The Origin of muddy sand sediments associated with mud volcanism in the Horonobe area of northern Hokkaido, Japan

Miyakawa, Kazuya   ; Tokiwa, Tetsuya; Murakami, Hiroaki  

The origin of mud from the mud-volcano-like sediments in the Horonobe area of northern Hokkaido, Japan was characterized by analyzing the mineral and chemical compositions of the mud. Mineral and chemical compositions of the mud are similar to those of the Hakobuchi Formation located at approximately 1500-2500 m depth. The results suggest that the mud originates from the Hakobuchi Formation, and also that the mud ascended from a depth of 1500-2500 m to ground surface. This result could be an exemplification of the occurrence of mud volcanism in oil and gas field and tectonic compressional region. This is useful information that should be taken into consideration in the planning and construction of underground facilities for geological disposal of HLW.