Popular article: https://www.nationalgeographic.com/...hquake-supersonic-supershear-speed-indonesia/ Nature.com paywall/abstract: https://www.nature.com/articles/s41561-019-0308-8 After analysis of the quake centered near Palu Indonesia that killed 2000+ people, it was determined that the velocity at which the tremor propagated the tear in the earth, this was "no ordinary earthquake". It is termed a supershear event. Supershear refers to the velocity of propagation of the rupture. These are rare. This one had lots of seismogaphs listening. Maybe our @davenn can point out this phenomenon using his output as recorded on his machine.