Buin Zahra Earthquake of 1 September 1962, Ms=7.2

This large-magnitude earthquake destroyed 91 villages, killing 12,225 and seriously injuring 2800 people (fatalities represented 11.6% of the total population of 142,029 in the epicentral area of 5387 km2) in the area south of the city of Qazvin. Over 21,300 houses in 300 villages were damaged beyond repair or partially destroyed, 180 of them with loss of life. The earthquake was associated with surface ruptures of unknown length along the Ipak fault with left-lateral, oblique-reverse displacements. Bedding-plane slips with a thrust mechanism (flexural-slip faulting), landslides, and reactivation of old thrusts or beddings (in the Eocene volcanic, Cretaceous carbonate rocks, or between the Cretaceous carbonates and the Eocene volcanics; due to gravity in Chenar, Kuh-e Miyanband, and Rostamabad) were misreported as coseismic surface ruptures by almost all the authors in the early 1960s. Discontinuous ruptures deduced from a few and widely spaced observations with unconfirmed total length of 55–103 (?) km, with vertical displacements of 40–76 cm, accompanied by left-lateral horizontal slip of 15–50 cm were reported by different authors. Bearing in mind that the western and central sections of the surface rupture were not visited; the highest displacements were recorded along the eastern segment of the coseismic surface rupture during the widely spaced observation traverses. The earthquake was also associated with intense bedding-plane slip with a thrust mechanism in the heavily fissured area (6 km long*2 km wide) of the Rudak-Tufak area in the Neogene and Pliocene molasse deposits, which was not identified by the original investigators. This indicated flexuralslip folding above the blind Tufak thrust to the north of the Ipak fault.

Ferdows Earthquake of 1 September 1968, Mw.6.4

The 31 August 1968 Mw7.1 Dasht-e Bayaz earthquake on the western segment of the Dasht-e Bayaz left-lateral strike-slip fault was followed 20h later by the 1 September 1968 Mw6.3 earthquake, and 3 days later by the second event of Mw5.5, with reverse fault focal mechanism in the Ferdows town region, about 70 km west of Dasht-e Bayaz. The first Ferdows earthquake almost totally destroyed the town of Ferdows (killing 750 out of 11,000 people) and ruined a number of villages that had been only slightly affected by the 31 August earthquake. The earthquake caused great damage at the extreme west part of the Dasht-e Bayaz meizoseismal area (Berberian, 2014).

Kanto, Japan Earthquake of 1 September 1923, Mw=7.9

At 02:58 UTC on September 01, 1923, a great earthquake with magnitude 7.9 occurred in Japan, killing about 142,800 deaths. The event is considered as one of the world’s most destructive earthquakes. Extreme destruction in the Tokyo – Yokohama area from the earthquake and subsequent firestorms, which burned about 381,000 of the more than 694,000 houses that were partially or completely destroyed. Although often known as the Great Tokyo Earthquake (or the Great Tokyo Fire), the damage was apparently most severe at Yokohama. Damage also occurred on the Boso and Izu Peninsulas and on O-shima. Nearly 2 m of permanent uplift was observed on the north shore of Sagami Bay and horizontal displacements of as much as 4.5 m were measured on the Boso Peninsula. A tsunami was generated in Sagami Bay with wave heights as high as 12 m on O-shima and 6 m on the Izu and Boso Peninsulas. Sandblows were noted at Hojo which intermittently shot fountains of water to a height of 3 m (Source: USGS). In Japan, September 1 is the Disaster Prevention Day. This day commemorates the 1923 Great Kanto earthquake and is a day on which disaster preparations are taken nationwide, especially in the Kanto region.