[1][3] The largest in the area since 1990, the earthquake registered 7.3 on the moment magnitude scale and was centered approximately 270 kilometers (170 mi) south of Mashhad on the village of Ardekul.

Damage was eventually estimated at $100 million, and many countries responded to the emergency with donations of blankets, tents, clothing, and food.

With 1 in 3,000 deaths in Iran attributable to earthquakes, a US geophysicist has suggested that a country-wide rebuilding program would be needed to address the ongoing public safety concerns.

[5] The earthquake was caused by a rupture along the Abiz Fault, part of the Sistan suture zone of eastern Iran.

Although the Iranian government had distributed more than 800 seismographs throughout the country, few had been placed in the Qayen region due to its desert climate and the remoteness of the area.

As a result of the dry climate, timber—a main component in building earthquake-resistant homes—is scarce in Qayen; homes are instead constructed of adobe.

[10]The earthquake was felt over an area of 500,000 square kilometers (193,051 sq mi), including in the cities of Mashhad, Kerman and Yazd.

[11] An initial report in The New York Times claimed that more than 2,000 people had died in the worst-affected area, with a further 394 in Birjand and two in the small town of Khavaf.

[12] In the wake of the earthquake and its aftershocks, every one of the 700 houses in the tiny village of Abiz, 90 kilometers (56 mi) east of Qayen, was destroyed, and 400 of its 1,200 residents killed.

[11] The United States Geological Survey estimated that 10,533 houses were destroyed; an additional 5,474 homes sustained varying degrees of damage.

[12] Many of the more seriously damaged homes were of simple construction, with walls made of mud, adobe, or brick packed 40–50 cm (16–20 in) thick.

Those near the epicenter still sustained severe damage due to the weight of the roofs and the weak joint connections between major structural elements of the buildings.

[8] Several thousand volunteers were brought in to join the search for survivors buried under mounds of brick and cement debris.

Local organizations, including the Iranian Red Crescent, sent 9,000 tents, more than 18,000 blankets, canned food, rice, and dates.

[9] France dispatched a cargo plane filled with blankets, tents, clothing, and food, while Swiss authorities sent a rescue team with dogs trained in search-and-rescue.

[9] Several aircraft carrying tents, blankets, and kerosene stoves from European and Arab countries arrived in Mashad on May 14.

[15] Representatives from the United States, calling the disaster a "humanitarian issue", said that despite their strong differences with Iran they would donate supplies and other aid if requested.

"[16] The United Nations have prepared a Common Country Assessment for Iran, which likewise states that "While adequate building regulations exist for large cities, it is generally believed that they are not rigorously adhered to... most of those who have suffered in recent major earthquakes have lived in small towns and villages.