The 4th February 1997 Bojnurd (Garmkhan) Earthquake in NE Iran: Field, Teleseismic, and Strong-Motion Evidence for Rupture Directivity Effects on a Strike-Slip Fault
Titel:
The 4th February 1997 Bojnurd (Garmkhan) Earthquake in NE Iran: Field, Teleseismic, and Strong-Motion Evidence for Rupture Directivity Effects on a Strike-Slip Fault
Auteur:
Hollingsworth, James Jackson, James Alarcon, John E. Bommer, Julian J. Bolourchi, Mohammad Javad
Verschenen in:
Journal of earthquake engineering
Paginering:
Jaargang 11 (2007) nr. 2 pagina's 193-214
Jaar:
2007-03
Inhoud:
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.