Speculation mounts over Iran’s nuclear capabilities after seismic event in Semnan Province. The wave signature suggests a nuke test but the depth defies convention.

The 4.6-magnitude earthquake that struck central Iran on October 5, 2024, has raised intense speculation that the event could have been an underground nuclear test. Much of the focus is on the seismic “signature” of the tremor and whether it resembles the patterns seen in past nuclear tests, despite a significant anomaly: the tremor occurred at a depth of 10 kilometers, unusually deep for a nuclear detonation.

A Question of Signature

Nuclear tests produce distinct seismic characteristics. According to Dr. Jeffrey Lewis, a nuclear weapons expert at the Middlebury Institute of International Studies, “Nuclear detonations release energy rapidly, generating a sharp, distinct P-wave signature on seismic graphs, unlike natural earthquakes, which typically produce more gradual waveforms.” Seismologists use this pattern to differentiate between natural quakes and explosions. However, the seismic data from the Iranian tremor has yet to display conclusive evidence of such characteristics.

Adding to the intrigue, seismic monitoring stations reported an absence of the compression waves typically seen in natural tectonic activity. These omissions often lead experts to speculate that an explosion could be responsible. Yet, as Dr. Lewis noted, “the absence of certain waves doesn’t automatically mean an explosion occurred—it simply raises questions that need further verification.”

Depth Raises Doubts

A significant factor fueling skepticism is the depth of the tremor, recorded at 10 kilometers beneath the surface. Nuclear tests, such as those conducted by North Korea, typically occur at much shallower depths, often between 200 to 500 meters. Dr. Paul Richards, a seismologist and expert in nuclear testing, explained, “For a nuclear test, 10 kilometers is extraordinarily deep. Most countries conduct such tests at shallower levels to control the detonation’s impact and avoid triggering deeper geological activity.”

This unusual depth, combined with the lack of surface disruption, as seen in satellite imagery, makes it difficult to conclude that the tremor was caused by a nuclear test. “There’s no visible evidence of cratering or surface uplift, which typically follows underground nuclear tests, especially at shallower depths,” noted Richards.

Resembling Other Nuclear Tests?

The magnitude of the Iranian tremor falls within the range of past nuclear tests—such as those in North Korea, which registered between 4.0 and 5.0 on the Richter scale. But experts warn against drawing premature conclusions. “The magnitude alone is not enough to confirm a nuclear test,” said David Albright, president of the Institute for Science and International Security. “You need to look at a combination of factors—depth, seismic waves, and any signs of radioactive fallout.” Without such confirmation, the event could very well have been a natural earthquake.

Moreover, the timing of the event amid heightened tensions between Iran and Israel has amplified the speculation. Iran’s rapid advances in its nuclear program have alarmed Western observers, and some analysts have questioned whether Tehran might use this moment to conduct a clandestine test. Yet as Dr. Lewis concluded, “It’s still far from proven. The lack of a comprehensive seismic signature and unusual depth both work against the hypothesis of a nuclear test.”

Looking Forward

The international community, including monitoring agencies like the International Atomic Energy Agency (IAEA), is expected to conduct further investigations into the event. While experts remain cautious, the tremor has reignited fears about Iran’s nuclear ambitions. If confirmed as a nuclear test, the geopolitical ramifications would be severe, potentially accelerating Israel’s defense posturing and triggering a global diplomatic crisis.

Until more conclusive evidence is gathered, experts advise against rushing to judgment. As Dr. Albright stated, “It’s essential to rely on verified data before making conclusions. A nuclear test would have clear, traceable markers, which, so far, haven’t surfaced in this case.”