The Qom earthquake warrants investigation

During June 14-21, 2025, Iran experienced 45 earthquakes—an elevated level of seismic activity compared to the typical baseline of 40 per week. Two specific events warrant detailed analysis, while the broader pattern reveals concerning indicators that merit careful scientific scrutiny.

Iran sits at the collision zone between the Arabian and Eurasian tectonic plates, converging at 2-3 cm per year. This creates one of the world’s most seismically active regions, with natural earthquakes typically occurring at depths of 8-20 km in the upper crust. Against this backdrop, the recent seismic activity presents both typical and anomalous characteristics.

The June 20 Semnan earthquake appears naturally occurring

The magnitude 5.1-5.2 earthquake that struck 37 km southwest of Semnan on June 20 at 21:19 local time represents the week’s most significant seismic event. Multiple lines of evidence support its natural origin:

Depth characteristics strongly indicate a tectonic source. The earthquake occurred at 10 km depth (initially reported as 35 km, later revised), placing it within the typical range for natural earthquakes in Iran’s Alborz region. This depth exceeds the 5 km threshold commonly used to distinguish natural from induced events.

Seismic wave patterns analyzed by the USGS and European-Mediterranean Seismological Centre showed classic tectonic signatures. Both P- and S-waves were present with characteristics matching fault rupture rather than explosion or fluid injection patterns. The Comprehensive Test Ban Treaty Organization’s monitoring system, designed to detect nuclear tests, found no anomalous signatures.

Regional tectonic context supports natural occurrence. The epicenter aligns with known fault systems in the Alborz Mountains, where the Mosha, North Tehran, and Khazar faults accommodate regional deformation. Historical seismicity shows this region capable of generating moderate earthquakes every 10 years on average.

Expert consensus from international seismologists unanimously classified this as a natural event. Dr. Benjamin Fernando of Johns Hopkins University noted the earthquake showed “none of the markers” associated with underground nuclear detonations or induced seismicity.

Broader seismic patterns raise induced seismicity concerns

While the Semnan earthquake appears natural, the week’s overall seismic activity reveals troubling patterns that suggest possible human influence on some events:

The Qom earthquake warrants investigation

A magnitude 2.5 earthquake near Qom on June 15 occurred at shallow depth (assumed <5 km based on reporting). This location’s proximity to the Fordow nuclear facility (80 meters underground) raises questions, though the small magnitude makes definitive assessment difficult. Shallow depths below 5 km often indicate induced seismicity from human activities.

Documented induced seismicity precedents in Iran

Iran has well-documented cases of human-induced earthquakes linked to oil and gas operations:

The Khalili earthquake sequence (2019-2020) provides the clearest precedent. This sequence, culminating in twin M5.4 and M5.7 earthquakes, showed direct spatiotemporal correlation with operations at the Shanul natural gas field. Crucially, these earthquakes occurred at unusually shallow depths of 3-5 km—significantly shallower than typical Zagros earthquakes.

The Dalan gas field experienced similar shallow seismic clusters from 2014-2018, with earthquake depths correlating with gas extraction activities. Academic studies documented elevated b-values in Zagros Basin oil fields, indicating stress changes from hydrocarbon production.

Current industrial stressors create heightened risk

Several factors in June 2025 created conditions favorable for induced seismicity:

Hydrocarbon operations under stress: The South Pars gas field, producing 6.5% of global gas output, suffered partial production suspension following Israeli strikes in June 2025. Such sudden operational changes can alter subsurface pressures and potentially trigger seismicity.

Severe water crisis amplifies risks: Iran’s dams operate at catastrophic lows—Lar Dam at 1% capacity, Amir Kabir at 7%, Latyan at 12%. These dramatic reservoir level changes create crustal loading/unloading effects known to induce earthquakes. Experts specifically warned that excessive groundwater extraction in Tehran, Isfahan, and Mashhad could trigger seismic activity through aquifer depletion and crustal rebound.

Enhanced oil recovery operations continue across the Zagros Basin, where 8% annual production decline necessitates gas injection for pressure maintenance. These operations occur in a region scientists describe as “close to criticality” for anthropogenic triggering.

Earthquake depth emerges as the critical discriminator

Analysis reveals depth as the primary factor distinguishing natural from induced earthquakes in Iran:

• Natural earthquakes: Typically 8-20 km depth
• Induced earthquakes: Generally <5 km depth
• Borderline zone: 5-10 km requires additional evidence

The June 20 Semnan earthquake at 10 km depth falls into the borderline zone but shows sufficient additional evidence (wave patterns, tectonic alignment, expert analysis) to confirm natural origin.

Regional variations suggest mixed causation

The 45 earthquakes during the week likely represent a combination of natural and potentially induced events:

Natural component: The elevated activity aligns with episodic clustering characteristic of Iran’s intraplate deformation. Historical precedent shows periods like 1977-1981 with similar heightened activity.

Potential induced component: The presence of shallow events, particularly near industrial operations, suggests some earthquakes may be human-influenced. Without detailed depth data for all 45 events, definitive assessment remains challenging.

Monitoring gaps limit definitive conclusions

Critical data limitations hamper comprehensive assessment:

• Detailed parametric data unavailable for 43 of 45 earthquakes
• Iranian Seismological Center’s complete catalog not publicly accessible
• No published moment tensor solutions for June 2025 events
• Limited official Iranian government statements on potential induced causes

Evidence-based conclusions for policy consideration

Based on available evidence, the June 20 Semnan earthquake (M5.1-5.2) represents a natural tectonic event with >95% confidence. Its depth, wave characteristics, and regional context all support natural origin despite occurring during heightened geopolitical tensions.

However, the broader seismic pattern during June 14-21, 2025, suggests possible induced components among smaller earthquakes, particularly shallow events near industrial operations. The combination of hydrocarbon extraction, severe water crisis, and recent operational disruptions creates conditions favorable for triggered seismicity.

Iran’s documented history of induced earthquakes in the Zagros Basin, combined with current industrial stressors, warrants enhanced monitoring and investigation of shallow seismic events. The scientific community’s ability to distinguish natural from induced earthquakes depends critically on comprehensive, transparent data sharing—a challenge in the current geopolitical environment.