Formation of Alpine mylonites and pseudotachylytes at the base of the Silvretta nappe, Eastern Alps

Recrystallization of quartz after low-temperature plasticity – The record of stress relaxation below the seismogenic zone

“…widespread occurrence of pseudotachylytes (e.g., Koch and Masch, 1992;Schmutz, 1995). Highlights -Stress relaxation after peak stress is recorded by quartz microfabrics -Slow relaxation rates are indicated by a marked CPO and SPO of new grains -Fast relaxation rates are indicated by isometric new grains with random texture -Microfabrics record specific deformation histories for different tectonic regimes…”

“…Although dynamic recrystallization has been the were deformed at lower greenschist facies conditions (DAV: e.g., Kleinschrodt, 1987;113 Stöckhert et al, 1999; Silvretta: e.g., Koch and Masch, 1992). These conditions correspond to 114 the base of the seismogenic zone in the continental lithosphere (e.g., Scholz, 2002) as well as 115 to the so-called brittle-viscous transition of quartz, depending on the stress-loading rates (e.g., (Laubscher, 1983;Thöni, 1988;Koch and Masch, 1992;Schmutz, 1995). Schmutz 149 (1995) suggested that the substratum was of similar composition as the Silvretta nappe.…”

“…Rb/Sr 150 and Ar/Ar isotopic investigations of pseudotachylytes indicate that they formed about 75 Ma 151 ago (Thöni, 1988;Bachmann et al, 2009). Fault rocks are assumed to have developed at 152 lower greenschist facies conditions between 300 and 400°C, as indicated by Alpine mineral 153 paragenesis in pseudotachylytes and host rock (Koch and Masch, 1992), which is consistent , 1978;Stöckhert, 1982;Kleinschrodt, 1987;Schulz, 1994). North to the DAV shear 167 zone, the metamorphic conditions were 450±50 °C with pressures of about 0.7 GPa based on 168 phase relations in the metapelitic Austroalpine basement rocks (Stöckhert, 1982(Stöckhert, , 1987 (Stöckhert, 1982(Stöckhert, , 1984Kleinschrodt, 1987;.…”

Seismic Slip in the Lower Crust Inferred from Granulite-related Pseudotachylyte in the Woodroffe Thrust, Central Australia

“…165, 2008 Seismic Slip in the Lower Crust through the base of the seismogoneic zone (e.g., PASSCHIER, 1982;KOCH and MASCH, 1992);2) downward propagation of dynamic fracture, which initiated within the seismogenic zone, to the plastic-dominated regime (SIBSON, 1980;SCHOLZ, 2002;LIN Figure 9 Schematic model of the propagation of seismic slip within a large-scale fault zone developed in continental crust (modified from LIN et al, 2005). The profile of shear resistance (s) with depth is arbitrary, given a geothermal gradient of 25°C/km (after SIBSON, 1983 andSCHOLZ, 2002).…”

Using the earthquake vapour theory to explain the French airbus crash

“…The earthquake vapour theory predicts that the initial temperature of earthquake vapour is identical to that of its origination hypocentre, which can range from 300 C to 1520 C (Koch and Masch 1992, Maddock 1992, Magloughlin 1992, O'Hara 1992, Spray 1992, Swanson 1992, Techmer et al 1992). The earthquake vapour's tremendous heat can increase the temperature of its surroundings.…”