17:15 〜 18:30
[SCG39-P13] Observation of localized slip events using viscoelastic fluids incorporating beads
キーワード：アナログ実験、brittle-ductile mixture、粘弾性流体
Slow earthquakes are distinctive quantized slip events with long duration and without seismic waves observed in regular earthquakes. Propagation of slip region in a single event and spatiotemporal coupling of these events, so-called migration, are noticeable features of slow earthquake. The fact that slow earthquakes are observed at the marginal region between seismogenic and aseismic steady sliding zones indicates brittle-ductile transition may be a key for the slow earthquake. This study intended to do an analog experiment using a mixture of beads and viscoelastic fluid situated between thin parallel plates. Here, viscoelastic fluids and beads are imitations of ductile and brittle rocks at a plate boundary.
The system was composed of zircon beads (φ=0.7 mm) dispersed in viscoelastic fluids. We used viscoelastic fluids consisting of (1) the mixture of emulsion and telechelic polymer and (2) wormlike micelles. These samples were placed between parallel acrylic plates, and the shear was applied by moving plates with a fixed speed or angular velocity. The gap between the plates was kept at 1 mm, so that the typical crack formation is constrained in the same order of this length. In this way, we could localized slip events and observe large-scale cooperative behavior between slip events. In the case of sample (1) that is known to produce fracture at low energy, we found spontaneous formation of lane structure through the appearance of localized crack in the sample. In the sample (2) with a large viscoelastic relaxation time, we found propagating behavior of the slip whose speed is less than the speed of the sound wave in the sample. In the talk, we will discuss the details of the experimental results and its theoretical interpretation.
The system was composed of zircon beads (φ=0.7 mm) dispersed in viscoelastic fluids. We used viscoelastic fluids consisting of (1) the mixture of emulsion and telechelic polymer and (2) wormlike micelles. These samples were placed between parallel acrylic plates, and the shear was applied by moving plates with a fixed speed or angular velocity. The gap between the plates was kept at 1 mm, so that the typical crack formation is constrained in the same order of this length. In this way, we could localized slip events and observe large-scale cooperative behavior between slip events. In the case of sample (1) that is known to produce fracture at low energy, we found spontaneous formation of lane structure through the appearance of localized crack in the sample. In the sample (2) with a large viscoelastic relaxation time, we found propagating behavior of the slip whose speed is less than the speed of the sound wave in the sample. In the talk, we will discuss the details of the experimental results and its theoretical interpretation.