SCRIPPS INSTITUTION OF OCEANOGRAPHY FACULTY CANDIDATE SEMINAR -
DATE: May 31st, Friday, 12:45 p.m.
LOCATION: Eckart 227
SPEAKER: Camilla Cattania
TITLE: Fracture mechanics insights into earthquake cycles at different scales: regional faults and small repeating earthquakes
In the last decades, the rapid development of geophysical networks, in-situ measurements and rock physics experiments has led to major steps in our understanding of fault friction. To grasp the implications of these discoveries for seismic hazard, we need to determine how fault physics at a microscopic scale affects the timing and extent of earthquake ruptures. In this talk I will present theoretical arguments from fracture mechanics, guided by numerical simulations, to explain fundamental features of seismic sequences: their degree of periodicity, recurrence interval, and distribution of earthquake magnitudes. Energy balance criteria predict that the timing and size of seismic events is controlled by the dimension of a fault relative to a characteristic length arising from frictional and elastic properties; for sufficiently large faults, this leads to power-law distributions commonly observed in earthquake catalogs. On the other hand, small faults can rupture in simple, quasi-periodic sequences of identical events. I will present theoretical arguments predicting the recurrence intervals and its scaling with magnitude, in agreement with observations of small repeating earthquakes worldwide.