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src/one-body-sample.parset

@@ -35,4 +35,28 @@ eta = 1
 model = Ruina
 
 [boundary.friction.ruina]
+# "For rocks, typical values of A and B range from 0.005 to 0.015"
+# -- Ronaldo I. Borja and Craig D. Foster:
+# Continuum mathematical modeling of slip weakening in geological systems
 a = 0.015
+
+# The second-order a and b terms in [..] are very important in
+# determining whether sliding is stable or unstable and (in appli-
+# cation to the Earth) whether an earthquake or stable creep
+# occurs. From [..], velocity strengthening and thus stable creep
+# occurs when a is greater than b.  If b > a, instability can occur
+# unless the "spring" supplying stress to the fault or sample is too
+# stiff
+# -- Norman H.  Sleep:
+# Application of a unified rate and state friction theory to the
+# mechanics of fault zones with strain localization
+
+# If a > b, the
+# overall change of f is positive, the friction is
+# velocity-strengthening, and only stable sliding is possible. On the
+# other hand, if a < b, the overall change is negative, the friction
+# is velocity-weakening, and dynamic instabilities can occur (e.g.,
+# Ruina, 1983). The situation a < b provides a necessary but not a
+# sufficient condition for instability.
+# -- Yehuda Ben-Zion:
+# Dynamic ruptures in recent models of earthquake faults