Criminals, terrorists and military have been using tunnels since long time to evade detection as surface based detection methods are ineffective underground .
Indian Border Security Force (BSF) troopers in Nov 2020 discovered an underground tunnel on the international border at Regal area in J&K`s Samba district, officials said. As per the BSF officials, the underground tunnel was discovered by a patrol party and “could have been used for infiltration from across the border”. DGP Dilbag Singh confirmed that a150-metre long underground tunnel was detected by the BSF at the International Border in Jammu and Kashmir’s Samba sector . The BSF officials further said that a massive anti-tunnelling operation was carried out jointly by the Army and police.
The tunnels threat was also faced by the U.S.-led coalition against ISIS who lurked in trenches and in a complex system of caves and tunnels. The tunnels, which are thought to run for at least two kilometers, seemingly helped hide tens of thousands of people, mostly IS fighters and their families, through much of the early part of the U.S.-backed Syrian Democratic Forces (SDF ) offensive.
The tunnel threat is also a serious and growing concern to U.S and Mexico, as they enable human trafficking and smuggling of drugs and weapons across the border. Recently a drug smuggling tunnel was discovered along the California-Mexico border that set the record for the longest cross-border tunnel ever discovered in Southern California. Around 170 tunnels have been discovered since 1990, Sixty percent of them discovered in just the last three years. According to the Department of Justice’s accounting, the tunnel was estimated to span 800 yards, and likely a lot longer due to its “zig-zagging” route, as Assistant U.S. Attorney Timothy Salel put it. “It is equipped with rail and ventilation systems, lights and a sophisticated large elevator leading from the tunnel into a closet inside the Tijuana residence,” he added. “It is one of the narrowest tunnels found to date, with a diameter of just three feet for most of the length of the passageway.”
It seems tunnel warfare is becoming a global concern as it is also common in other parts of the world such as Iraq, Afghanistan and Syria where rebels use them in combating Assad’s military forces. In between 2001 and 2016, India has discovered at least eight tunnels originating from across the border along Pakistan, at an average of one every two years. And, only one of these is suspected to have been dug for drug running, while the others are linked to possible or successful infiltrations.
Many defense companies including Lockheed Martin and Raytheon, are developing technologies for detecting tunnels. U.S. government is earmarking $120 million over the next three years and partnering with Israel to help develop a new tunnel detector. The goal, U.S. Defense Department spokesman Christopher Sherwood told Foreign Policy, “is to establish anti-tunnel capabilities to detect, map, and neutralize underground tunnels that threaten the U.S. or Israel…”
In recent Israel-Palestine Conflict, Israel had carried out massive ground offensive to wipe out a vast network of tunnels built by Hamas. Israel sees these being built for infiltrating its territory, smuggle large amounts of firearms and other sabotage materials into the Gaza Strip. The Israel Defense Forces has installed a series of underground sensors ( acoustic and seismic ) along the northern border in order to detect any new subterranean tunnels entering Israeli territory from Lebanon.
In December 2018, the IDF launched Operation Northern Shield, an effort to locate and destroy tunnels dug by Hezbollah into northern Israel from southern Lebanon. In total, the military said it found six such passages and rendered them inoperable — either using explosives or filling them with concrete — last year. The IDF believes that the six tunnels dug by Hezbollah into northern Israel were built with the specific purpose of allowing thousands of Hezbollah terrorists to stage an infiltration attack on military and civilian targets in northern Israel as a surprise opening maneuver in a future war.
Prime Minister Benjamin Netanyahu and Defense Minister Avigdor Liberman in oct 2017, hailed the IDF for destroying an attack tunnel from the Gaza Strip discovered near a kibbutz inside Israeli territory, with the two leaders attributing its discovery to Israel’s new “breakthrough technology.” I told you many times before that we are developing breakthrough technology to deal with the tunnel threat,” said Netanyahu at the start of the meeting. “We are implementing it. Today, we located a tunnel and we destroyed it.”
Earlier, the military said the tunnel had been under surveillance for an extended period of time and was under active construction at the time of the demolition. “The tunnel was detonated from within Israel, adjacent to the security fence,” the military said in a statement. IDF spokesperson Lt. Col. Jonathan Conricus said the tunnel was at least two kilometers away from the Israeli town and did not pose a threat to its residents. Liberman also said no Israelis were endangered by the tunnel.
In March 2016, the Indian BSF floated a Request for Proposal for a pilot project of the CIBMS in two five-km patches along the border in Jammu. Tata Power SED and Dat Con have won a pilot project of the Ministry of Home Affairs to install an integrated border-guarding system to test technology for preventing infiltration, especially by detecting cross-border tunnels as well as possible entries through aerial and underwater routes. Called the Comprehensive Integrated Border Management System (CIBMS), it is a major counter-infiltration measure to prevent cross-border terror attacks and detect tunnels.
The Israeli government, has been developing such a system for at least the past five years. Codenamed project “Hourglass,” Israel has already invested the U.S. dollar equivalent of more than $60 million in the system, involving help from more than 100 technologies, defense, and engineering companies. Remote controlled robots help agents explore tunnels that are too risky for humans to enter.
Western sources reported on 11th March 2016, that the new weapon, dubbed the “Underground Iron Dome,” can detect a tunnel, then send in a moving missile ton blow it up. The new weapon is not counter measure only against threat from Gaza and Lebanon but against Iran nukes too. US intelligence sources disclosed only that new weapon is equipped with seismic sensors to detect underground vibrations and map their location before destroying them. Western experts haven been talking for years about a secret Israeli weapon capable of destroying Iran’s Fordo nuclear facility, which is buried deep inside a mountain not far from the Shiite shrine city of Qom.
They suggested that this hypothetical weapon could be slipped through the Fordo facility’s vents, thread its way through the underground chambers and take down the illicit enrichment facility. It was discussed again three years ago, when the Israeli Air Force on 23rd Aug. 2013 blew up the Popular Palestinian Front-General Command underground facility at Al-Naama on the South Lebanese coast, 15 km south of Beirut.
DHS Science and Technology Directorate Tunnel Detection and Surveillance requirements
Cross-border tunnels are dug by transnational criminal organizations to smuggle contraband into the U.S. . Current detection capabilities rely on random tips and laborious human intelligence (HUMINT) collection. When tunnels are discovered, U.S. Customs and Border Protection (CBP) and U.S. Immigration and Customs Enforcement (ICE) have limited ability to exploit the tunnel to arrest and prosecute those involved in creating and using the tunnel.
• Tunnel Prediction, Investigation and Remediation.
This project seeks to identify and evaluate available technology to enhance DHS’s ability to perform forensic analysis of a detected tunnel to support investigations and prosecutions. Current efforts include evaluating unmanned ground systems to investigate found tunnels
without having to put an agent in the tunnel.
• Cross Border Tunnel Detection Program.
This project seeks to develop a system or combination of high performance systems for CBP to detect and locate clandestine cross-border tunnels along the southwest border.
• Through Wall / Floor Void Detection.
This project seeks to develop a man-portable system capable of scanning large areas of interest to locate hidden tunnels and/or man-made voids behind walls or floors, enhancing the ability of law enforcement officers to quickly detect tunnels in typical urban environments
Using the Department of Homeland Security (DHS) Science and Technology Directorate developed tunnel detection tools and systems, CBP will be able to accurately detect and locate clandestine tunnels. This will result in a reduction in the flow of contraband smuggled into the U.S. via tunnels, keeping hundreds of tons of drugs off U.S. streets, while saving thousands of CBP labor hours. Tunnel forensic tools/processes enable ICE to assign attribution for tunneling activity and thereby increase the arrest and prosecution of individuals involved in the creation and use of tunnels for illegal activity.
Challenge of detecting terror tunnels
Part of the problem in detecting tunnels, say experts like Paul Bauman, a Canadian geophysicist, is the ground itself. Finding what is under the surface is not as simple as shooting radar or electromagnetic waves into the ground, he said. With underground cracks, water tables, tree roots and caves, it is hard to tell what is and is not a tunnel, he said. Mr. Bauman, who has worked with the Israel Defense Forces in their efforts to find tunnels, said most of the devices used for tunnel detection were developed for industries to find oil or mineral deposits, not drug tunnels.
Carey M. Rappaport, a professor of electrical and computer engineering at Northeastern University in Boston, said the depth of many tunnels also posed a technological challenge. Some can be as deep as 90 feet, beyond the reach of most ground radar devices and sensors. “Soil is very good at keeping secrets,” said Mr. Rappaport, who has also worked with the United States and Israeli governments on tunnel detection methods.
Recently, the Science and Technology Directorate of the Department of Homeland Security concluded that none of the current methods used to detect underground tunnels were “necessarily suited to Border Patrol agents’ operational needs.”
Tunnel detection technologies
Most of the existing tunnel detecting capabilities are modifications of existing equipment originally used to detect land mines or natural gas and oil deposits. More sensitive, sophisticated techniques are needed to find tunnels, which exist between those two extremes of size and depth.
An Israeli company, Magna, has proposed digging a 70-km tunnel along the Israel-Gaza border, equipped with a sensitive alert system. The system shall be able to localize attack tunnel, estimate how many people are in it, and can monitor the progress of digging. Now, Israel Hayom reports, Israel has built its own network of defense tunnels along the Gaza border, with the cooperation of the United States.
Some of the technology solutions that have been found useful for tunnel detection are
The effectiveness of tunnel detection devices is directly related to the geophysical characteristics of local soil. DHS&T is in the process of collecting and compiling a database of existing derived and new geological and geophysical survey data along the border where the tunneling is most probable.
Ground penetrating Radar
Special radar mounted on a vehicle that uses pulses of appropriate frequency and ultra wideband waveforms to form an underground image. Its promising technology widely used in quality-testing roads, and to find unmarked graves, locate utility lines, trace subsurface geology, sweep for mines and search archaeological sites.
However, some of its limitations of this method is that it does not work well in most mediums like clay and rarely penetrates deeper than 40 ft and produces lots of false alarms even at shallow depths leading to waste of time and money. The developers are concentrating their efforts on using much lower frequencies that can penetrate the ground much deeper, and a sophisticated new imaging technology that can display clear pictures of deep tunnels.
The R2TD system developed by the U.S. Army Engineer Research and Development Center is a ground-penetrating radar capable of detecting tunnels deep within the ground. It employs sensors to detect acoustic and seismic energy. The R2TD system can be mounted in a vehicle or carried by a soldier to an area of interest, and is capable of transmitting data to a remote post for data analysis.
Surprise attacks by enemy troops hiding in tunnels are difficult to predict, although radar technology can help by finding the tunnels. The Rapid Reaction Tunnel Detection (R2TD) system can detect the underground void created by a tunnel, as well as electrical cables or devices within the tunnels, using ground-penetrating-radar (GPR) technology. Because adversaries are continually adapting—using different tunnel depths and more complex maze configurations—the analysis software for the R2TD system must be continually refined, with increased transmit power for greater ground penetration.
The system has been in use since 2014 and typically requires only one day of training by combat engineers for fully effective operation and results. Because adversaries are continually adapting—using different tunnel depths and more complex maze configurations—the analysis software for the R2TD system must be continually refined, with increased transmit power for greater ground penetration.
The National Centre for Excellence in Technology for Internal Security (NCETIS) at IIT-B, which also has people working with other IITs, has developed a Ground Penetrating Radar (GPR) at 920MHz, which can not only detect tunnels but also landmines buried in soil. “Right now, we testing the equipment for ruggedness. We have a mandate that it needs to work in all terrains and conditions and once the ruggedness test is complete, we will begin the field trials in February,” Seema Periwal, project manager, NCETIS told TOI from Mumbai.
Seismic Sensor Network
The underground activity like digging, drilling, scraping, jack-hammering, can create the ground disturbances or vibrations that travel through the ground in the form of seismic waves and can be detected by seismic sensors like geophones buried under the ground.
Signal processing is the critical technology for extraction of data and intelligence from the signals generated by seismic sensors, identifying the type of activity like digging, walking, vehicle etc. and also the localization of activity. The intelligent algorithms can also filter out non-threatening vibrations, from construction equipment, traffic on nearby roads and underground subways, in order to minimize false alarms.
Full waveform inversion (FWI) is a powerful tool to determine quantitative image of Earth subsurface from seismic data . It was initially applied to two-dimensional media due to highly computer demanding calculations. However, the earth is three-dimensional and its highly heterogeneous geology requires a full 3D modelling of the wavefield. Due to the recent increase in computational power several applications of 3D FWI on real datasets have been presented using acoustic approximation (Plessix and Perkins, 2010). The extension of waveform inversion to 3D elastic case with realistic model size is still a challenging task even on current computer architecture.
Recently Researchers from Kansas Geological Survey, Lawrence, Kansas, USA, have applied time-domain 3D elastic full-waveform inversion (FWI) to a known tunnel constructed 10 m below the surface with no distinguishing surface expressions. “Multicomponent inversion experiments that use an initial model estimated from surface wave methods suggest that the vertical sources and the combination of vertical and longitudinal receivers result in the clearest image of the tunnel. We obtain an approximate 3D image of the tunnel using 24 vertical sources and 720 vertical and 720 longitudinal receivers. We find that increasing the number of vertical sources to 216 does not significantly improve the details of the tunnel,” write the Authors.
A combination of Airborne SAR (Synthetic Aperture Radar) and GPR has also been proposed for underground tunnel detection. Some of the other proposals include measuring electrical resistivity through metal electrodes, microgravity sensors and detecting muons underground brought by cosmic rays hitting the earth.
Laser scanning shows up hidden military tunnels on Alcatraz
High-tech radar and laser scans have uncovered a hidden military traverse (defensive trench system) dating from the mid-19th century underneath the infamous Alcatraz penitentiary, in San Francisco Bay, according to research led by Binghamton University, New York.
Binghamton archaeologist Timothy de Smet and colleagues used terrestrial laser scans, ground-penetrating radar data and georectifications (the process of taking old digitized maps and linking them to a coordinate system so that they can be accurately geolocated in 3D space) to find and assess the historical remains beneath the former recreation yard of the Alcatraz penitentiary, run by the US Department of Justice from 1934 through 1963.
This nondestructive research method revealed that remnants of buried structures, including a “bombproof” earthwork traverse along with its underlying vaulted brick masonry tunnel and ventilation ducts, ran east to west beneath the recreation yard of the Alcatraz penitentiary. The work has been published in a paper, The fate of the historic fortifications at Alcatraz island based on terrestrial laser scans and ground-penetrating radar interpretations from the recreation yard, in Near Surface Geophysics.
Tata on Indo-Pak border: Using tech to detect tunnels, check infiltration
The 3,323-km India-Pakistan border consists of the international border guarded by the BSF and the Line of Control guarded by the Indian Army. The border is porous which makes infiltration by terrorists possible. In the 1990s, the government had erected a fence along the entire length of the India-Pakistan border. But infiltration was still taking place. Over the years, the BSF has found several tunnels starting from Pakistan reaching into India.
The CIBMS will integrate sensors, communication, infrastructure, response, and command and control. It will be a force multiplier for the BSF. “Manpower along the border is irreplaceable, but human endurance has its limitations. With the CIBMS we can detect threats in advance and ensure a counter attack. This would lead to reduction in casualties,” said an official. An important component of the CIBMS is satellite imagery. The BSF is already using satellite imagery. It helps the security forces in learning about the terrain and military fortifications across the border. It also helps in better planning of operations and border defences on the Indian side. However, not being real-time, they are not always useful.
The BSF has also planned to use UAVs as part of the CIBMS to launch them when required to gain real-time data. Sensors such as those placed underground will also form part of the CIBMS. These sensors sound an alarm when a person steps near them, alerting the troops. “The firms will also be setting up equipment to detect cross-border tunnels and possible infiltration through aerial and underwater means. The pilot project will be the first to test such technology,” said an official. The RFP had stated the requirement of tracking low-level flying threats from 500 m up to 1 km. Sonars will also be used to track underwater movement.
In a statement issued yesterday, Tata Power said, “CIBMS will establish a seamless multi-tier security ring at the border using a variety of sensors, to identify any infiltration attempts and will be operational 24x7x365. Sensors (viz. Thermal Imager, Radar, Aerostat with EO Payload, Optical Fibre Intrusion Detection System, Unattended Ground Sensor and Underwater Sensor) can detect threats not just on the surface but also underground and underwater.”
Robots in anti-tunnel campaign
IDF‘s military robot Talon 4 has been used in dangerous tunnels on the Gaza Strip border instead of soldiers to reduce risks to troops. Another are lightweight, portable Carrier Robots, that would be carried by soldiers on their backs. They shall be capable of scanning areas underground for many hours, mapping entire buildings and terror tunnels. It is equipped with cameras, sensors, and a communications system capable of transmitting signals from underground. The groundbreaking technology will allow soldiers to understand the exact appearance of any structure, helping them avoid the dangers of underground or urban combat as explained by Major Lior Trablisi, the head of the IDF’s robot and technology unit.
“Robotic-laptop soldier,” will assist soldiers from the Combat Engineering Corps and infantry soldiers in underground combat. The idea of this small-scope robot is to take on dangerous missions, including patrolling and collecting information for the fighters on the ground. This will solve many of the problems soldiers are forced to face when operating underground, such as collapsing walls and lack of oxygen and lighting.
Tunnel Detection And Underground Warfare Market
The tunnel detection and underground warfare market is forecast to gorw in a very rapid pace. In recent conflicts (e.g. in Afghanistan, Iraq, Syria, and Gaza), while certain countries had overwhelming combat power, their adversaries resorted to a much more primitive combat strategy: the use of underground tunnel warfare. Prime examples include structures built by Al-Qaeda or the Taliban, tunnels by ISIS, Hamas attack tunnels, and the Hezbollah tunnel network.
The challenge posed by these terror tunnels and underground combat tactics is key for the emergence of transformational counter-terror technologies, including detection mechanisms and unmanned systems for tunnel warfare. The maturity and deployment of these technologies are projected to alter the asymmetric landscape of subterranean warfare into a symmetric encounter, and affect both border security and urban warfare tactics. The challenge posed by these clandestine tunnels and underground structures is the key to the emergence of transformational counter-terror technologies and tactics. The maturity and deployment of these technologies are forecasted to alter the asymmetric landscape of subterranean warfare into a symmetric encounter.
Proactive Subterranean Warfare, in which remotely controlled “Detect and Kill” subterranean robots will search, locate and destroy the adversary tunnels and buried structures. These new developments will lead to a new era of Subterranean Warfare, in which armed forces and law enforcement agencies will employ a host of ever-changing technologies and tactics.
Some of the key companies are Elbit Systems, Elpam Electronics, Advanced Geosciences, Inc. (AGI), Allied Associates Geophysical Ltd.
CGG Canada Services Ltd, Exploration Instruments LLC , Lockheed-Martin, Geogiga Technology Corporation, Geomar Software Inc.,
Geometrics, Inc., Geonics Ltd., Geophysical Survey Systems, Inc, Interpex Ltd., Mount Sopris Instruments, PetRos EiKon Incorporated,R. T. Clark Co. Inc., Sensors & Software Inc., Vista Clara Inc., Zonge International, Inc., Geomatrix Earth Science Ltd, Northwest Geophysics, Spotlight Geophysical Services, and Quest Geo Solutions Limited
References and resources also include: