Iran: An earthquake — or a secret underground nuclear test?

Days after news broke of the earthquake in Iran’s Semnan province, speculation has continued on social media that the tremors were caused by Tehran’s first nuclear test.

At 10:45 pm on Saturday, the University of Tehran’s seismography centre announced that a 4.4-magnitude earthquake had shaken the city of Aradan in Iran’s Semnan province, with tremors also felt in parts of eastern Tehran.
The epicentre of the earthquake, which occurred 12km below ground, were recorded as 35.42° north and 52.78° east.
Hours after the news broke, social media users began speculating that the Tehran regime had attempted to conduct its first underground nuclear test, presumably as a deterrent measure against Israeli attacks on its territory.
These speculations came as Islamic Republic officials and Revolutionary Guard commanders repeatedly threaten that if economic, political and military pressures on the country intensify, Tehran will alter its military defence doctrine — a change that would require amending the Iranian leader’s fatwa on the illegality of nuclear weapons.
Nevertheless, the NorNews news website, which operates informally as the Islamic Republic’s National Security Council main information outlet, dismissed the nuclear speculation as “rumours” and once again stressed that nuclear testing contradicts Iran’s nuclear and defence doctrine.
However, the notion that Iran would never conduct such a test without announcing a change in policy does not necessarily stand up to scrutiny.
In 2019, the Foundation for Defense of Democracies, a Washington-based think tank, released a report that Iran had begun a program to build underground nuclear testing sites, known as the “Field Project”.
The foundation has been sanctioned by Iran’s Foreign Ministry for five years for “producing and disseminating lies, encouraging, consulting, lobbying, and negative propaganda campaign against the Islamic Republic with the aim of playing an effective role in imposing and intensifying economic sanctions”.
According to its 2019 report, its researchers “identified the likely location (in an area southeast of Semnan) where underground non-nuclear explosives tests were conducted in 2003 as part of developing seismic methods of measuring the yield of an underground nuclear explosive.”
This raises the prospect that the earthquake reported in Semnan could be connected to Tehran’s first nuclear test.
While Iran has previously acknowledged the existence of the “Imam Khomeini” space centre and missile headquarters southeast of Semnan, the site is more than 100 kilometres from the earthquake’s epicentre.
However, some social media users continue to speculate that perhaps Iran has an undeclared underground nuclear facility in Semnan province, preferring to use it as a testing site instead of conducting them at a well-known facility such as Natanz.
Tehran has consistently failed to disclose its nuclear activities to the International Atomic Energy Agency. At the same time, Iran is an earthquake-prone country, and tremors like these are not uncommon or strange.