Precursory changes in seismic velocity for the spectrum of earthquake failure modes

Abstract

Temporal changes in seismic velocity during the earthquake cycle have the potential to illuminate physical processes associated with fault weakening and connections between the range of fault slip behaviors including slow earthquakes, tremor and low frequency earthquakes1. Laboratory and theoretical studies predict changes in seismic velocity prior to earthquake failure2, however tectonic faults fail in a spectrum of modes and little is known about precursors for those modes3. Here we show that precursory changes of wave speed occur in laboratory faults for the complete spectrum of failure modes observed for tectonic faults. We systematically altered the stiffness of the loading system to reproduce the transition from slow to fast stick-slip and monitored ultrasonic wave speed during frictional sliding. We find systematic variations of elastic properties during the seismic cycle for both slow and fast earthquakes indicating similar physical mechanisms during rupture nucleation. Our data show that accelerated fault creep causes reduction of seismic velocity and elastic moduli during the preparatory phase preceding failure, which suggests that real time monitoring of active faults may be a means to detect earthquake precursors.

On the evolution of elastic properties during laboratory stick‐slip experiments spanning the transition from slow slip to dynamic rupture

“…Scuderi et al . [] expanded our understanding of the acoustic signature of stick‐slip failure and showed that precursory changes in seismic velocities occur for the complete spectrum of laboratory slip behaviors from slow slip to fast, dynamic rupture.…”

“…The mechanics of regular, fast earthquakes in particular are based on laboratory studies of stick‐slip frictional instability [e.g., Scholz , ]. More recently, laboratory observations have begun to illuminate the mechanics of slow slip and oscillatory stable sliding [e.g., Kaproth and Marone , ; Ikari et al ., , ; Leeman et al ., ; Scuderi et al ., ]. Other experiments have documented a strong relation between acoustic transmissivity and fault strength [ Kame et al ., ; Nagata et al ., , ], or elastic wave velocities and the evolution of rock damage [ Schubnel et al ., ].…”

Decrease in Seismic Velocity Observed Prior to the 2018 Eruption of Kīlauea Volcano With Ambient Seismic Noise Interferometry

“…This behavior was recently shown to be present prior to the full spectrum of earthquake failure modes in a laboratory study (Scuderi et al, 2016) and has also been proposed by other authors as a mechanism for velocity decrease prior to eruptions at volcanoes (Carrier et al, 2015;Rivet et al, 2014). Volcanic eruptions occur when the buildup of pressure in the magma reservoir exceeds the strength of the surrounding rock mass in the volcanic edifice, often resulting in increased seismic activity.…”

Frictional Behavior of Input Sediments to the Hikurangi Trench, New Zealand

“…This potentially unstable behavior at low effective stress implies that slow slip could extend even to shallower depths within faults of this composition. This observation highlights that it is the frictional stability, which includes effects of effective stress together with the stiffness of the fault and the loading system (Leeman et al, 2016;Scuderi et al, 2016) that controls the behavior of slip events and not the friction velocity dependence alone. We note that the cutoff velocity of~1 μm/s that we see in the plate-rate experiments is higher than the average slip velocities of the SSEs observed in the northern Hikurangi subduction zone (1-3 cm/day or~0.12-0.35 μm/s; Figure 4).…”