Surface Physicochemical Properties of Smectite‐Rich Fault Gouge: A Case Study of the Japan Trench Plate‐Boundary Fault

Abstract

The frontal part of the Japan Trench plate‐boundary fault is enriched in low‐strength smectite, and this material characteristic is thought to be a factor for the large fault slip during the 2011 Mw 9.0 Tohoku‐oki earthquake. In this study, we evaluated the surface physicochemical properties of the particles that constitute the fault zone and examined their effect on the rheological properties of the fault. Measurements of the zeta potential, surface free energy and pore size distribution indicate that the interparticle interaction in the in situ state is very weak. This means that the viscous resistance is low, which may have contributed to the large fault slip during the earthquake. The interparticle distance appears be longer than the energetically stable state, which may reflect a transitory state after the earthquake. Changes in microscopic interparticle interactions during coseismic and interseismic periods may influence the rheological behaviors of the Japan Trench plate‐boundary fault.

Heterogeneities in the Cohesion of the Deposits of the 2021 Tajogaite Eruption of La Palma (Canary Islands, Spain)

“…In recent years, other lines of work have been added to the study of the dynamics of the volcanic edifice, based on the analysis of the physicochemical properties of the eruption materials, especially the more geotechnically unstable tephra deposits [6][7][8]. The superficial physicochemical properties of the samples allow us, among other things, to determine the states of aggregation and, therefore, to know the microstructure of these deposits, their water-retention capacity, as well as their cohesion and rheological properties if flows as landslides or lahars [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”