Bojnurd earthquake(1997)

States KHORASAN SHOMALI
Published At 11 February 1997

Summary

The Bojnurd region of NE Iran experienced a Mw 6.4 earthquake on February 4, 1997.

Description

  The Bojnurd region of NE Iran experienced a Mw 6.4 earthquake on February 4, 1997.By combining results from teleseismic body-waveform analysis, field observations of structural damage, coseismic deformation, geomorphology, and analysis of the resulting strong ground-motions, we build a coherent picture of the faulting associated with this earthquake. The earthquake resulted from almost pure right-lateral strike-slip motion (0.5–1.0 m), which ruptured a ∼15 km long section of fault, striking ∼340° at its northern end, which changes to ∼320° at its southern end. This fault can be seen clearly on the geological map and satellite imagery. The village of Sheikh lies ∼10–15 km SE of the fault rupture, yet was severely damaged during the earthquake. Analysis of strong-motion records, recorded by the Building and Hazard Research Center of Iran, particularly their significant duration, the polarization of the fault-normal component, and the velocity pulse, indicates a probable directivity effect, in which the rupture propagated from north to south, towards the village of Sheikh.   The 4th February 1997 Bojnurd (Garmkhan) Earthquake in NE Iran