[S-CG45] Science of slow-to-fast earthquakes

[SCG45-P15] Relationship between kinetics of mineral vein formation and earthquake cycles around seismogenic megathrusts, subduction zones

*最首 花恵¹、大坪 誠¹ (1.国立研究開発法人産業技術総合研究所)

キーワード：鉱物脈、地震発生周期、反応速度論、シリカ鉱物、カルサイト

Mineral veins can be widely recognized around seismogenic megathrusts, subduction zones. Water-rock interaction could affect the mechanical and hydrological properties of rocks, and it may have important roles on earthquake occurrence and its recurrence. Many previous works have shown the results of analysis and formation models of mineral veins such as quartz, calcite and other mineral veins in and around seismogenic zones to suggest the relationship between vein formation and earthquake cycles. However, the discussion of these relationship is inadequate given the kinetics. Under some natural conditions, the time scale of vein formation tends to be slower than that of earthquake recurrence intervals (e.g., 100 to 1000 years orders). In particular, the precipitation of quartz to form the observed quartz vein requires a lot of water and time, depending on the fracture size, pressure, temperature, and fluctuation of pressure and temperature conditions. Two previous works compared the timescales of quartz vein formation and that of earthquake recurrence (Saishu et al., 2017; Ujiie et al., 2018). In this study, we summarize and discuss the relationship between minerals in veins and timescales of vein formation around seismogenic megathrusts, subduction zones following some previous works.

References:
Silica precipitation potentially controls earthquake recurrence in seismogenic zones, H. Saishu, A. Okamoto, M. Otsubo, Scientific Reports, 7, 2017.
An Explanation of Episodic Tremor and Slow Slip Constrained by Crack-Seal Veins and Viscous Shear in Subduction Melange, K. Ujiie, H. Saishu, A. Fagereng, N. Nishiyama, M. Otsubo, H. Masuyama, H, H. Kagi, Geophysical Research Letter, 45, 11, 2018.