Triggered tremor may simply be clock- advanced failure, which could make it useful as a widely available ambient tremor and perhaps slow slip ‘meter’. Volcano Island Triggering depends on more than wave amplitude. Posited Triggering Wave Amplitudes Vancouver Island (Cascadia) Triggering depends on more than wave amplitude. Posited Triggering Wave Amplitudes Vancouver Island (Cascadia) Rubinstein et al. (2008)

Fault population with failures at a ~constant rate. Clock-Advance Model

Perturbation advances (or delays) the failure times. Clock-Advance Model

perturbed rate unperturbed rate relationship between clock- advance & fault proximity to failure [This underlies the ‘Dieterich (1994)’ aftershock model. Used in Beeler & Lockner (2003), Kaneko & Lapusta (2008), & others.] Rate tests.

Cascadia Ambient Tremor Probabilities & Teleseism Origin Times

Sichuan P-Waves Ambient Tremor Triggered Tremor 2008 Wenchuan Earthquake Waves Arrive During ETS Event & Trigger Tremor seconds

Peru P-Waves Comparable 2007 Peru Earthquake Waves Arrive During Inter-ETS Time -> No Triggering seconds

Denali Waves -> Instrumentation Matters! PNSN PNSN & CNSN

Amplitude tests: bigger perturbations -> bigger summed tremor.

Suggestion of a scaling… data are noisy and scant.