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Data from: Gouge stability controlled by temperature elevation and obsidian addition in basaltic faults and implications for moonquakes

Cao, Shutian1; Zhang, Fengshou1; An, Mengke1; Elsworth, Derek2; He, Manchao3; Liu, Hai4

Published Jun 07, 2023; Updated Dec 06, 2023 on Dryad. https://doi.org/10.5061/dryad.bvq83bkfn

Data files

Dec 06, 2023 version files 3.18 MB

Abstract

Basalt is a major component of the earth and moon crust. Mineral composition and temperature influence frictional instability and thus the potential for seismicity on basaltic faults. We performed velocity-stepping shear experiments on basalt gouges at a confining pressure of 100 MPa, temperatures in the range 100-400°C and with varied obsidian contents of 0-100 wt.% under wet/dry conditions to investigate the frictional strength and stability of basaltic faults. We observe a transition from velocity-neutral to velocity-weakening behaviors with increasing obsidian content. The frictional stability response of the mixed obsidian/basalt gouges is characterized by a transition from velocity-strengthening to velocity-weakening at 200°C and another transition to velocity-strengthening at >300°C. Conversely, frictional strengths of the obsidian-bearing gouges are insensitive to temperature and wet/dry conditions. These results suggest that obsidian content dominates the potential seismic response of basaltic faults with the effect of temperature controlling the range of seismogenic depths. These observations contribute to a better understanding of the nucleation mechanism of shallow seismicity in basaltic faults.