How did Israel discover Iran’s underground bunkers? Technology that revealed all the secrets involved…

Modern espionage techniques are challenging all old notions. Until now, it was believed that underground bunkers were safe, but the US and Israel discovered them, even killing Iran’s Supreme Leader. What kind of technology can detect even these underground bunkers? This article explains the full details in a simple way.

On the night of March 7, 2026, more than 80 Israeli aircraft dropped 230 bombs on Tehran and central Iran. The bombing destroyed an underground ballistic missile storage and production site, from where hundreds of Iranian armed forces operated. A day earlier, on March 6, 50 Israeli fighter jets dropped approximately 100 bombs, completely destroying a secret bunker beneath Tehran’s leadership complex. This isn’t the first time; Israel also targeted several underground bunkers in Iran in 2025. The question is: how are these underground bunkers discovered? How did Israel know that there are bunkers hidden under the rocks and underground?

In fact, modern reconnaissance technology has made it much easier to detect underground objects. Satellites orbiting thousands of kilometers in space, combined with high-tech sensors and artificial intelligence, can even detect activities going on underground.

Why is it so difficult to hide a bunker?

While building an underground bunker is easy, completely concealing one is now nearly impossible. This is due to the basic requirements of a bunker. Any such facility requires electricity to operate, so that machines and computers can function. People need breathable air, for which ventilation shafts are built. Scientists, soldiers, and technicians constantly come and go inside. Communication systems are essential to maintain contact with the outside world.

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Furthermore, construction involves heavy machinery, digging, and removing large amounts of soil. These activities become the bunker’s greatest vulnerability, as modern intelligence technology can detect these signals to detect hidden locations.

Today’s spy satellites use highly advanced radar technology. The most important of these is synthetic aperture radar (SAR). This technology sends microwave waves from the satellite toward the ground. These waves can penetrate soil and rocks up to several meters deep.

When these waves hit a void, tunnel, or bunker underground, their reflection pattern changes. Scientists analyze this change to infer the location of underground structures. America’s secret spy satellites use this same technology, enabling day-and-night, all-weather surveillance.

Thermal imaging technology also comes into play. Heat emanates from any machine, computer, or human being. When machines operate inside an underground bunker, this heat slowly reaches the surface. Satellite infrared sensors detect this abnormal temperature on the ground surface. This difference is especially noticeable at night, as the surrounding ground becomes cooler, while the soil above the bunker becomes warmer.

Electronic signals and vibrations

Not just radar or temperature, but electronic signals can also reveal hidden targets. Intelligence agencies use signals intelligence (SIGINT), a technique that detects radio waves and other electronic signals.

Unusual radio communications, increased satellite phone usage, or high power consumption from an area can all come to the attention of intelligence agencies. Furthermore, electromagnetic signals from machines are also difficult to detect.

Ground vibrations during construction also provide important clues. When tunnels or bunkers are built inside mountains, blasting, drilling, and heavy machinery cause ground vibrations. Global seismic sensor networks record these vibrations, and through scientific analysis, they can determine that these are not natural earthquakes, but construction activity.

Drones, spy planes and the role of AI

High-altitude aircraft and drones have become crucial in modern reconnaissance. High-altitude reconnaissance aircraft and drones, capable of maintaining long-term airtime, can continuously monitor an area. Their multi-spectral cameras capture images simultaneously in different wavelengths, allowing for more detailed analysis of ground activities.

Additionally, satellite analysis based on artificial intelligence (AI) has become a powerful tool for reconnaissance. AI can detect even the smallest changes by comparing old and new satellite images. If a new road is suddenly built in an area, the soil color changes, trees are removed, or vehicle traffic increases at night, the AI system can quickly identify these changes and provide information.

How was the Fordow nuclear facility discovered?

A prime example of the combined use of all these technologies is the exposure of Iran’s secret nuclear facility, Fordo. The facility was being built deep within a mountain, and Iran believed it would remain undetected. However, various satellite monitoring systems detected signs of unusual structures within the mountain. Thermal sensors detected hot air escaping from ventilation vents. Communication signals and construction activities further fueled suspicion.