Figure 2
From: Fast-moving dislocations trigger flash weakening in carbonate-bearing faults during earthquakes
Emission spectra for selected masses recorded with a Pfeiffer Quadstarquadrupole mass spectrometer during three slip pulses of 1.5 mm and one of 50 mm (experiment s1187).
Each slip pulse was performed at σn = 10 MPa, Vtar = 1 m/s and inside a vessel to capture gas emission from the shear zone. The diagram reports the ion current relative to the initial atmospheric background value. Significant variations are recorded in case of mass 2 (H2), mass 44 (CO2), mass 15 (CxHy). After each pulse the vessel was opened to remove the gouge from the sliding surfaces and to restore the initial atmospheric conditions. A delay was observed between the slip pulse and the detection of the compounds due to the travel time of the gas through the capillary and the acquisition time of the mass spectrometer.
