Cohabitation of slow and moderate-sized earthquakes in blueschist-facies linked to fault microstructure and rheology

We explore how slow earthquakes and moderate-sized intraplate earthquakes cohabit in blueschist-facies at intermediate-depth. We measure friction on blueschist gouges at elevated temperatures (100-500℃), effective normal stresses (60-220 MPa) and fluid pressures (30-75 MPa) to represent conditions along the descending slab and to link observed rheology to microtextural evolution. We identify a transition into potentially unstable rheologies at elevated temperatures >200℃ - meeting the conditions necessary for generation of earthquake instabilities at blueschist-facies depths. This transition is controlled by a mechanism of thermally-activated dissolution creep indicated by the observed presence of dissolved glaucophane and suggestive of dilation-suppressing fluid-assisted mass transfer processes. Reducing effective normal stress results in increasingly unstable behavior as evident in&n..., , # Cohabitation of slow and moderate-sized earthquakes in blueschist-facies linked to fault microstructure and rheology

Dataset DOI: [10.5061/dryad.np5hqc06w](10.5061/dryad.np5hqc06w)

## Description of the data and file structure                                                       

The friction-displacement data for all shear experiments on blueschist gouges.

**File list and description (files found within DataS1.zip)**

Huang_et_al_2025_BS_100.xlsx – The shear displacement (mm) (column 1) and coefficient of friction (dimensionless) (column 2) data for Experiment BS-100.

Huang_et_al_2025_BS_200.xlsx – The shear displacement (mm) (column 1) and coefficient of friction (dimensionless) (column 2) data for Experiment BS-200.

Huang_et_al_2025_BS_300.xlsx – The shear displacement (mm) (column 1) and coefficient of friction (dimensionless) (column 2) data for Experiment BS-300.

Huang_et_al_2025_BS_350.xlsx – The shear displacement (mm) (column 1) and coefficient of friction (dimensionl...,