Monitoring tunnels for vibrations and deformations is not only critical during the construction phase but also their service life.
In 2012, the Tokyo-bound Sasago Tunnel suffered significant damage when nearly 150 concrete ceiling panels collapsed and crushed three vehicles, including a van carrying six people that caught fire. The deficiencies in mounting components of the ceiling panels were to blame.
But, are tunnels safe during an earthquake?
A common belief that underground structures are safer because they move with the soil, while structures above ground sway back and forth during the earthquakes appears to be misleading. The impact of earthquakes on tunnels can be severe due to ground failures such as liquefaction, strong ground shaking, and fault crossing.
Liquefaction takes place when saturated soft soil deposits loose load-carrying capacity during strong shaking. This phenomenon can cause the ground surrounding tunnels to deform and shift, with potentially severe impacts. The slope instability and fault crossings may also create permanent deformations leading to a collapse of the tunnel.
After the 1906 San Francisco earthquake, the Wrights railway tunnel in southern Santa Cruz mountains was closed for more than a year due to the collapse of approximately 100-m-long part crossing the San Andreas Fault Zone. Another railway tunnel crossing the White Wolf Fault was seriously damaged during the 1952 magnitude 7.5 Kern County earthquake associated with this fault (Kontogianni and Stiros, 2003).
In 1999 a magnitude 7.2 hit the Duzce region in Turkey. Close to the fault rupture, twin highway tunnels on the major highway connecting Ankara to Istanbul were under construction. The tunnels were partially collapsed due to intense pulses of earthquake motion (near-fault effects) as their lines cross the shear zone of the North Anatolian Fault.
The excavation process during tunnel construction may itself trigger microearthquakes. The vibrations, therefore need to be monitored to identify such seismic activity whether they create any movements or cracks on the tunnel surface. The monitoring vibrations is also needed to estimate the rock formations ahead of the tunnel face to optimize the excavation parameters. Besides, the infrastructure surrounding the tunnel including buildings must be monitored especially in case of construction of new subway (metro) lines.
Structural health monitoring (SHM) system is essential for the seismic resilience of tunnels. A robust real-time SHM system not only allows for assessment of accelerations and deformations (displacements and strains) in tunnel linings but also facilitates the implementation of adaptive risk management. Such a system can assist the officials to make informed and timely decisions to protect people (such as drivers or construction workers) from life-threatening conditions. For example, the highway tunnel can be closed to traffic before any severe consequences take place. Such pro-active actions would not only save lives but also avoid liabilities.
QuakeLogic is the only company providing cloud-based AI-powered disaster risk management solutions to prevent and reduce human and economic losses risen during and after earthquakes. Our cutting-edge technology platform performs real-time autonomous structural assessments using sensor data and sends rapid notifications after an event with the level of shaking intensity and whether structural integrity is compromised. For tunnels, our platform provides meaningful and easy-to-understand information immediately after an earthquake. This timely and critical information helps the officials to plan their emergency response. We also provide a web-based display where the sensor information can be monitored in real-time. This solution can provide great benefits especially for tunnels under construction phase.
For emergency measures and safety of tunnels, QuakeLogic provides advanced monitoring systems together with real-time and autonomous data analytics.
Last reviewed: 2026-07-04
Executive Summary
Structural health monitoring uses sensors, data acquisition, signal processing, and engineering interpretation to track condition and detect abnormal response. This article has been expanded as an engineering resource for readers evaluating structural health monitoring concepts, instrumentation choices, and monitoring workflows. The discussion is educational and should be paired with project-specific review by qualified engineers, applicable codes, owner requirements, and equipment documentation.
Key Takeaways
- Define the engineering objective before selecting sensors, test equipment, trigger thresholds, or reporting workflows.
- Use calibrated instrumentation, documented installation practices, time synchronization, and traceable data handling where measurement quality matters.
- Interpret measured data in context: site conditions, structure type, noise environment, sampling rate, bandwidth, and boundary conditions all affect conclusions.
- Use authoritative references and project-specific criteria rather than relying on generic thresholds or unsupported performance claims.
Technical Explanation
In practical structural health monitoring work, the engineering system is more than a sensor or a test platform. A credible workflow includes the measurement objective, instrument selection, mounting or boundary conditions, sampling and timing strategy, data validation, event or response detection, engineering review, and reporting. Weakness in any part of that chain can reduce confidence in the final interpretation.
For monitoring applications, engineers should document sensor orientation, coupling, environmental exposure, dynamic range, frequency bandwidth, data logger configuration, clock synchronization, communications, and maintenance procedures. For testing applications, engineers should document input motion, fixture design, payload properties, control limits, safety interlocks, acceptance criteria, and post-test data review.
Engineering Applications
| Application | Engineering Question | Typical Evidence Needed |
|---|---|---|
| Research and education | How does a structure, component, or sensor respond under controlled conditions? | Test plan, calibrated data, input motion, boundary conditions, and repeatable observations. |
| Critical infrastructure | Is the asset response normal, changing, or potentially unsafe after an event? | Baseline data, event records, thresholds, inspection workflow, and engineering sign-off. |
| Industrial facilities | Can monitoring support operational continuity and response decisions? | Site-specific criteria, reliable telemetry, alarm logic, maintenance records, and documented procedures. |
People Also Ask
What should be specified before buying equipment?
Specify the measurement objective, frequency range, amplitude range, environment, data format, timing needs, installation constraints, reporting requirements, and applicable standards or owner criteria.
Why do references and standards matter?
They provide terminology, acceptance criteria, test methods, and documentation expectations. They do not replace engineering judgment, but they reduce ambiguity and make results easier to review.
How should data quality be checked?
Review calibration status, timing, clipping, sensor orientation, signal-to-noise ratio, environmental artifacts, data completeness, and whether the record supports the engineering decision being made.
Related QuakeLogic Resources
- HOW STRUCTURAL HEALTH MONITORING CAN MAKE ISTANBUL A SMART CITY?
- EVACUATE OR NOT—A DILEMMA OF HOSPITALS AFTER AN EARTHQUAKE AND HOW CAN ARTIFICIAL INTELLIGENCE HELP?
- COMPARING EXPECTED EARTHQUAKE SHAKING IN ISTANBUL WITH THE 1999 M7.6 IZMIT EARTHQUAKE
- PROPER MONITORING CAN PROVIDE EARLY DAMAGE DETECTION AND INTERVENTION FOR DAMS
- Related QuakeLogic products and technologies
- QuakeLogic Engineering Blog topic resources
References
Recommended Diagram or Download
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Discuss a Monitoring or Testing Application
QuakeLogic supports seismic monitoring, earthquake early warning, structural health monitoring, infrasound monitoring, vibration monitoring, data acquisition, and shake table testing applications. For project-specific guidance, contact QuakeLogic with the asset type, measurement objective, site constraints, and required deliverables.
