The city of

Kashan Kashan (; ) is a city in the Central District (Kashan County), Central District of Kashan County, in the northern part of Isfahan province, Isfahan province, Iran, serving as capital of both the county and the district. History Earlies ...

Iran Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the nort ...

was struck by a major earthquake just before dawn on 15 December 1778. The earthquake had an estimated magnitude of 6.2 . There was widespread damage in the area around the city, with most buildings destroyed. More than 8,000 people were killed.

Tectonic setting

The continuing

continental collision In geology, continental collision is a phenomenon of plate tectonics that occurs at Convergent boundary, convergent boundaries. Continental collision is a variation on the fundamental process of subduction, whereby the subduction zone is destroy ...

between the Arabian plate and Eurasian plate drive the active tectonics of Iran. The convergence between the two plates is accommodated across a broad zone from the

Zagros fold and thrust belt The Zagros fold and thrust belt (Zagros FTB) is an approximately long zone of deformed crustal rocks, formed in the foreland of the collision between the Arabian plate and the Eurasian plate. It is host to one of the world's largest petroleum ...

in the southwest to the

Alborz The Alborz ( ) range, also spelled as Alburz, Elburz or Elborz, is a mountain range in northern Iran that stretches from the border of Azerbaijan along the western and entire southern coast of the Caspian Sea and finally runs northeast and merge ...

mountain range in the north. Kashan lies close to the boundary between the

Central Iranian Range The Sahand-Bazman Volcanic and Plutonic Belt or the Sahand-Bazman Igneous Arc or the Central Iranian Range is a mountain range that is made by (both extrusive and intrusive) igneous and pyroclastic rocks. Located East and almost parallel to the Z ...

to the southwest and the Central Basin to the northeast. The mixed

volcanic rock Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and me ...

s underlie these areas and

metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, caus ...

s of the Sanadaj-Sirjan zone (SSZ), the plutonic rocks of the Urumieh-Dokhtar magmatic arc and the

sedimentary rock Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or de ...

s of the Central Basin. The area is affected by a mixture of active

thrust fault A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. I ...

ing and

strike-slip In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

faulting. The main active structure near Kashan is the Qom-Safreh Fault, a northwest–southeast trending right lateral strike-slip fault zone, which runs along the northeastern boundary of the SSZ. It has been associated with several historical earthquakes.

Earthquake

The earthquake had an estimated magnitude of 6.2 . It has been attributed to rupture along the Kashan segment of the Qom-Safreh fault. The mainshock was followed by a sequence of

aftershock In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in Epicenter, the same area of the Mainshock, main shock, caused as the displaced Crust (geology), crust adjusts to the effects of the main shock. Large earthq ...

s, which continued for about a month.

Damage

The area of damage extended as far north as Sen Sen and as far south as

Qohrud Qohrud () is a village in, and the capital of, Qohrud Rural District of Qamsar District, Kashan County, Isfahan province, Iran Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asi ...

. Most houses and other buildings in Kashan were destroyed. The Bazaar and the Jameh Mosque of Kashan were badly damaged, although the brick-built minaret of the latter survived. Water supplies were badly affected in the area.

Casualties

At least 8,000 casualties were recorded as a result of the earthquake. The death toll was further increased by a

cholera Cholera () is an infection of the small intestine by some Strain (biology), strains of the Bacteria, bacterium ''Vibrio cholerae''. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea last ...

outbreak.

Aftermath

Reconstruction of Kashan began soon after the earthquake, under the orders of

Karim Khan Zand Mohammad Karim Khan Zand (; ) was the founder of the Zand dynasty, ruling all of Iran (Name of Iran, Persia) except for Khorasan province, Khorasan from 1751 to 1779. He also ruled over some of the Caucasus, Caucasian lands and occupied Basra f ...

, preventing a mass exodus of the survivors. Under the leadership of 'Abd al-Razzaq Khan, the fourth governor of Kashan, a new bazaar was built directly on the basement of the old building and the Jameh Mosque of Kashan was extensively rebuilt, as were many other public buildings.

References

{{Earthquakes in Iran Earthquakes in Iran 1770s earthquakes History of Isfahan province Kashan 1770s in Iran 1778 in Asia 1778 disasters