Publication Date:
2017-04-04
Description:
Despite considerable effort over the past several decades, the mechanics of
earthquake rupture remains largely unknown. Moderate- to large-magnitude earthquakes
nucleate at 7–15 km depth and most information is retrieved from seismology, but
information related to the physico-chemical processes active during rupture propagation is
below the resolution of this method. An alternative approach includes the investigation of
exhumed faults, such as those described here from the Adamello Massif (Italian Alps), and
the use of rock deformation apparatus capable of reproducing earthquake deformation
conditions in the laboratory. The analysis of field and microstructural/mineralogical/geo-
chemical data retrieved from the large glacier-polished exposures of the Adamello (Gole
Larghe Fault) provides information on earthquake source parameters, including the
coseismic slip, the rupture directivity and velocity, the dynamic friction and earthquake
energy budgets. Some of this information (e.g., the evolution of the friction coefficient with
slip) can be tested in the laboratory with the recently installed Slow to HIgh Velocity
Apparatus (SHIVA). SHIVA uses two brushless engines (max power 280 kW) and an air
actuator in a rotary shear configuration (nominally infinite displacement) to slide solid or
hollow rock cylinders (40/50 mm int/ext diameter) at: (1) slip rates ranging from
10 lm s-1 up to 9 m s-1; (2) accelerations up to 80 m s-2; and (3) normal stresses up to
50 MPa. In comparison to existing high-speed friction machines, this apparatus extends the
range of sliding velocities, normal stresses and sample size. In particular, SHIVA has been
specifically designed to reproduce slip velocities and accelerations that occur during
earthquakes. The characterization of rock frictional behavior under these conditions, plus
the comparison with natural fault products, is expected to provide important insights into
the mechanics of earthquakes.
Description:
Published
Description:
95-114
Description:
3.1. Fisica dei terremoti
Description:
reserved
Keywords:
friction
;
pseudotcahylite
;
high velocity friction experiments
;
04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
book chapter
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