Garmkhan Earthquake of 04 February 1997, Mw 6.6
At 10:37:47 UTC on Tuesday, 4th February 1997, an earthquake with magnitude of Mw=6.6 and epicentral coordinates 37.71N and 57.49E occurred in Garmkhan mountainous area about 30 kilometers north of the Bojnord city in Northern Khorasan Province. Due to the earthquake, 84 people were killed. The event was associated with a strong foreshock that led to relatively less loss of lives. More than 170 villages were damaged and three villages containing Naveh, Ghezel Ghan and Sheikh were 100% destroyed. The strong motion of the event was recorded in 14 stations of the Iran Strong Motion Network (ISMN) including Ashkhaneh, Kalaleh, Maraveh Tappeh, Raz, Rezvan, Emam Gholi, Neyshaboor, Barezoo Dam1, Gonbad-e-Kavoos, Mashhad1, Robat*, Farooj*, Gifan* and Bojnoord* in which maximum corrected PGA=192 cm/s2 was recorded in the Bojnoord* station. Hollingsworth et al. (2007) showed that 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. 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, 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.
Dehkharghan-Tabriz Earthquake of 05 February 1641, Ms 6.8
On Friday 5th February 1641, there was suddenly and quite unexpectedly a terrible earthquake at Tabriz, accompanied by violent aftershocks. The heavy soil vacillated above its solid base, like a disturbed leaf, or like water shaken in a vase. There was a terrible rumbling within the depths of the earth and then the earthquake, which shook the buildings of the town and caused them to collapse and disintegrate. A large and vast building of marvellous height, situated at the centre of the city, a souvenir of the kings of ancient times, fell in the twinkling of an eye, and covered the earth with debris. Neither did the earthquake spare the famous building of Usta Shagerd, which collapsed on a number of camels and other animals sheltering inside against the cold and snow of winter. This is not all. The domes and minarets of mosques reaching towards the sky, to dizzy heights, collapsed, shattered and crumbled into pieces, which fell to the ground and burst into fragments. The roof of the famous and superb building of Shamkazan, situated at some distance from the town, beside the river Shur collapsed, leaving only the surrounding walls, which shook on their foundations and split in four directions, forming the four stumps still visible today. As for the houses, villas, baths and caravansera, how can we enumerate the ruins, the number of men and animals, furniture and personal effects, goods and wealth, entombed in the bosom of the earth! Only after twenty or thirty days of searching and clearing the rubble could the corpses and treasures be recovered, and then with considerable difficulty. If the town of Tabriz had much to suffer from the earthquake, the loss of men and animals, buildings destroyed, it was even worse in neighbouring areas, such as Khosrowshah, Osku and in the village of Dehkharghan. The thick surface-crust of the earth was split open following the terrible aftershock, creating fresh springs with black water in whose flow it was reflected: After three days there was another terrible aftershock and the waters disappeared, although it produced some small springs and accumulations of black water like the preceding shock. These waters existed for the duration of the aftershock and disappeared as soon as it had finished. They say that a shepherd was driving his sheep in front of him one day, when, in a certain place, during an aftershock, the crust of the earth cracked and formed an abyss, by which the shepherd and part of his flock were engulfed alive, none of them reappearing. An entire village, built in the fold of a rocky mountain, was covered and disappeared completely, an aftershock having dislodged the solid blocks of rock, which shattered, crumbled and enveloped it with a bed of stones and debris.
Reference:
- Hollingsworth J., Jackson J., Alarcon J., Boomer J., and Bolourchi M.J, (2007), “The 4th February 1997 Bojnourd (Garmkhan) earthquake in NE Iran: Teleseismic, and strong-motion evidence for rupture directivity effects on a strike-slip fault”, Journal of Earthquake Engineering, 11: 193-214, DOI: 10.1080/13632460601031078.
- Berberian, M. and Arshad, S., (1976), ” On the evidence of the youngest activity of the north tabriz fault and the seismicity of Tabriz city”, Geol. Surv. Iran, 39, 397-418.
The most important worldwide earthquakes (M>7) of this day
| Date | Time | Y | X | Depth | Mw | Region | Refrence |
| 1921/02/04 | 8:22:41 | 15.681 | -90.805 | 15 | 7 | Guatemala | USGS |
| 1932/02/04 | 21:18:9 | 26.5 | 62.25 | 35 | 5.8 | Iran | ISC |
| 1934/02/04 | 13:27:0 | 30.65 | 51.64 | 65 | 6.3 | Iran | AMB |
| 1971/02/04 | 15:33:29 | 0.653 | 98.711 | 30 | 7 | Nias region, Indonesia | USGS |
| 1975/02/04 | 11:36:07 | 40.641 | 122.58 | 33 | 7 | Liaoning, China | USGS |
| 1976/02/04 | 9:01:43 | 15.324 | -89.101 | 5 | 7.5 | Guatemala | USGS |
| 1997/02/04 | 10:37:51.19 | 37.7385 | 57.2892 | 35.7 | 6.6 | Garmkhan | EHB Bulletin |