[6] The ISB is characterized mainly by normal faulting of late Quaternary age, indicating active extensional tectonics, as recognized throughout the Basin and Range province to the south.

[9][10] The shock measured 6.5 on the moment magnitude scale and had a maximum Mercalli intensity of VIII (Severe), based on damage reports.

Analysis of seismic waveforms supports left-lateral slip on a fault plane with a strike of 172°, dipping steeply to the west.

[1] Left lateral strike-slip movement on a north–south trending fault came as a surprise as it does not seem to match the known orientation of the regional stress field.

A press release from Major Tom of the Sawtooth National Forest reported small avalanches were as far north as Bonners Ferry, near the Canadian border.