Premium
Carbonate Fault Mirrors With Extremely Low Frictional Healing Rates: A Possible Source of Aseismic Creep
Author(s) -
Park Yohan,
Hirose Takehiro,
Ree JinHan
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2021gl093749
Subject(s) - creep , fault (geology) , geology , carbonate , seismology , materials science , geotechnical engineering , composite material , metallurgy
Frictional healing of faults is a key mechanism controlling fault strength recovery, which enables the development of repeating earthquake cycles. Carbonate fault rocks are commonly characterized by shiny mirror‐like surfaces, sometimes referred to as fault mirrors. Despite the prevalence of fault mirrors in both natural and experimental fault rocks, their frictional healing behavior has not yet been studied. We measured frictional healing rates of experimentally simulated carbonate fault mirrors and found them to be an order of magnitude lower than those of other carbonate fault rocks. Microstructurally, the fault zone of fault mirror specimens is characterized by densely packed sintered nanogouges. We infer that this tight nanograin structure hinders the chemical and physical processes that cause frictional healing. Fault mirrors showing extremely low frictional healing rates are likely to creep aseismically.