Brittle-Failure (BF)
Brittle-Failure (BF) : earthquake Sometimes used in volcano seismology (See: Chapter 13 of this Manual) to distinguish earthquakes dominated by brittle processes (frictional slip or formation of a tensional crack) from those in which fluids are thought to play an active role (such as "LP" earthquakes or "harmonic tremor". The designation "BF earthquake" is generally synonymous with "high-frequency", "volcano tectonic", or "A-type" earthquake