Life in the Gaza metro
Hamas came to power there in the mid-2000s after Israel withdrew its troops from the Gaza Strip, deported the Jewish population and fenced off the area. The aim of the Palestinian movement is to destroy Israel militarily, and to this end its members stockpile weapons, train militants, and periodically fire rockets at Jewish settlements. But there is a problem: Israel completely controls the skies of Gaza and proves this by periodically destroying military facilities on the ground.
Hamas therefore decided to hide underground, and what started as smuggling tunnels eventually grew into a vast system of underground bunkers and communication routes.
According to Israeli data, all of Hamas’s basic infrastructure is underground: headquarters, barracks, hospitals, weapons and ammunition depots. Same work. contains and hostages captured in the October 7 attack.
The “Gaza metro” shelters, which journalists call the underground system, are connected by underground passages whose exits to the surface are located in the basements of buildings, courtyards or vacant lots. Moreover, many underground passages were designed so that they could be used to ambush advancing Israeli troops – for example, by ducking out of a tunnel close to the road.
Some passages are directly below the ground surface, but significant tunnels are usually 30 m deep and can exceed 70 m. They can be destroyed with a heavy bunker bomb, but only a few meters if the location of the tunnel is known. Hamas keeps the coordinates of the tunnels secret and Israel is forced to find the underground passages on its own. This task is incredibly complex and absolutely impossible to solve without modern technology.
Hyperspectral “eyes” of Israel
To search Israeli tunnels according to SpyTalk uses A comprehensive reconnaissance system, an important element of which is hyperspectral cameras mounted on drones. Conventional cameras record information about the brightness of an object in three ranges: red, green and blue. By combining these you can create the illusion of a full color picture for the human eye. This is how color photography works. Moreover, even three colors are enough to distinguish a fresh tomato from a moldy tomato, or an apple from an orange.
A hyperspectral camera stores data for each pixel in not three, but tens and hundreds of spectral ranges (“colors”) from mid-IR to ultraviolet. By looking at an object with such “eyes”, you can understand its chemical composition and obtain information about its internal structure.
In this case, neither IR radiation nor visible light penetrates the ground and carries information only about the surface layers. But a SpyTalk source claims that the sensors used by Israel allow drones to detect underground cavities, see through concrete pipes, as well as detect fumes leaking from explosives and carbon dioxide exhaled by people. socialbites.ca tried to find out whether this is really possible.
How to look from the ground?
“At first glance, the optical aperture is not very suitable for studying underground structures due to the opacity of the soil. Carbon dioxide breathed by humans can leak into the soil, but in very small quantities. The atmosphere already contains 0.035% carbon dioxide, and the concentration above the tunnel will change slightly due to breathing,” Russian Academy of Sciences Unique Vitold Pozhar Sciences, head of the department of acoustic-optical information systems at the Scientific and Technological Center of Instrumentation (STC UP RAS), told socialbites.ca.
According to him, the presence of carbon dioxide or explosive components can be determined under controlled laboratory conditions by characteristic changes in the spectrum (“color” of the air). When shooting an area with a drone the camera will be exposed to a lot of noise, but even without this it will be difficult to distinguish underground crowds from natural fluctuations in carbon dioxide concentrations. The same goes for explosives. However, searching for tunnels can be made easier if you look for spots with a characteristic shape.
“When viewed from above, the tunnels should look like long lines with many branches. Accordingly, if we took a hyperspectral image of an area and see a series of carbon dioxide spots in a line across it, this can no longer be attributed to either natural fluctuations or noise.
“If this line passes where the tunnel can be found, according to common sense and other types of exploration, then we can talk about the discovery of an underground structure with high probability,” explained Witold Pozhar.
In his opinion, the best way would be to dig your own tunnel and see if the ground above it is different when you “look” into any gap. The algorithm can then be trained to precisely detect such signs elsewhere. However, the expert emphasizes that the methods he describes are just assumptions. The SpyTalks source may be wrong about the technology Israel uses, and the scientist himself prefers to search for underground structures in the microwave range using radar.
According to another Russian expert, the tunnel could potentially be detected by indirect signs through changes in the vegetation above it.
“If the walls of the tunnel are reinforced with concrete, this disrupts the natural movement of moisture in the ground. Accordingly, the shallowness of the location may affect the appearance of the grass in the hyperspectral image. Such cameras are actively used in agriculture; especially for accurately measuring the moisture saturation of plants.”
– Samara University professor Nikolai Kazansky explained to socialbites.ca.
Both scientists tend to believe that hyperspectral imaging was most likely used as part of a broader set of measures to search for tunnels and did not work like a “magic lantern” that automatically highlighted underground structures.
Radars, robots and underground drones
US Army Veteran and Underground Warfare Explorer John Spencer on Podcast Series approved The importance of hyperspectral photography with unmanned aerial vehicles in the search of Hamas tunnels was mentioned, and other technological techniques used by Israel’s specialized special forces unit, Yahalom, were also mentioned.
Soldiers rely heavily on ground-penetrating radar, whose beams can penetrate the ground, according to Spencer.
A portion of the radio emission at each depth is reflected and sent back to the radar, and the properties of the signal thus obtained depend on the properties of the material. Particularly metal and concrete objects can be seen in the radio range, clearly indicating the existence of a tunnel.
However, a major drawback of GPR is the need to press it directly into the ground to get the clearest image possible. It will perform much worse when placed on a drone or aircraft.
Yahalom also has mobile drilling rigs for more “conservative” tunnel detection. It is also possible to throw explosives or introduce other equipment into an underground shaft.
After the tunnel is found, if necessary, warriors from the Samur detachment and the Yahaloma unit are lowered here. It is equipped with a radio communication system suitable for underground operation, a navigation system and thermal cameras to navigate and see the enemy in complete darkness. Additionally, soldiers use different types of drones. Flying ones are used to automatically map the tunnel; Spencer doesn’t specify how to do this, but they likely carry lidars (laser “radars”) and/or back-illuminated cameras to create accurate 3D models of underground structure.
Ground-based drones (tracked or wheeled) are equipped with a machine gun or grenade launcher and a remote control system. This allows Hamas fighters to look in every corner and target Israeli soldiers without risking their lives.
Also participating in underground operations are dog handlers with dogs trained to work underground. Despite the advancement of technology, dogs continue to be the most useful and effective tool for detecting both explosives and human scent.
Experiments with “sponge bomb”
If it is decided to destroy the tunnel, a guided anti-bunker bomb such as the GBU-28 can be dropped on the given coordinates. It has the capacity to penetrate 30 meters of soil or 7 meters of concrete, and then 300 kg of tritonal will explode inside. If bombing is not desired for any reason, the exit from the tunnel can be blocked using explosives or bulldozers.
In addition, Israel was actively involved in the war with Hamas before it started. tried with a sponge bomb (sponge bomb, reference to the cartoon character SpongeBob). There are no explosives inside, just two liquids separated by a partition. When liquids are mixed, they foam and harden quickly, sealing the tunnel. It is probably similar to polyurethane foam, but like polyurethane foam it is much more durable.
But despite all the technological innovations, combating Hamas’ underground tunnels will be incredibly difficult. The Palestinian movement is aware of many of Israel’s tactics and is ready to counter them, from digging tunnels and setting traps to using hostages as human shields.