When Minutes Matter: How can LiDAR prepare us for ‘The Big One’
- Clinton Bravo
- Oct 30
- 12 min read
“The Big One” – a term that sends a chill down the spine of Metro Manila residents – refers to a long-anticipated massive earthquake expected along the West Valley Fault. Seismologists project a magnitude 7.2 shake that could devastate the metropolis and nearby provinces. In such a scenario, every second counts. The ability to quickly assess damage, ensure structural safety, and coordinate rescue efforts can mean the difference between life and death. Modern technology is stepping up to help meet this challenge. One standout tool is LiDAR surveying, which uses lasers to create precise 3D maps of our surroundings. In this article, we’ll explore in simple terms how LiDAR works and how it can be a game-changer in preparing for and responding to a major earthquake from safeguarding bridges and buildings to preserving cultural heritage. When minutes matter, LiDAR offers eyes and insights that can save lives.
Metro Manila sits atop several fault lines, with the West Valley Fault being the most notorious. Government studies have painted a grim picture of what a magnitude 7.2 earthquake “The Big One” could bring. Estimates based on a joint Philippine-Japan study suggest around 33,500 fatalities and 113,600 injuries could occur in Metro Manila and surrounding areas. Beyond the human toll, we could see thousands of buildings collapsing or severely damaged, fires from broken gas lines, and critical infrastructure crippled. Bridges might fail, isolating parts of the city; older buildings could crumble, and heritage structures would be at grave risk.
In such a disaster, time becomes the scarcest commodity. The first 72 hours after a major earthquake are often called the golden period for saving trapped survivors. Quick decisions are needed: Which bridges can ambulances still use? Which buildings are too unsafe to enter? Where are the hardest-hit areas that rescuers should prioritize? These decisions depend on information – and rapid surveying and mapping is the key to getting that information. This is where LiDAR, with its speed and precision, becomes invaluable. By preparing before the quake and acting swiftly after, LiDAR can help Metro Manila be more resilient to the Big One’s impacts.
LiDAR for Stronger Bridges
A collapsed bridge span in a recent incident highlights how undetected structural weaknesses can lead to sudden failures. Proactive LiDAR surveys help identify cracks and vulnerabilities in bridges before disasters strike, potentially preventing such catastrophic collapses.
Bridges are literal lifelines in any city – and even more so during an earthquake when they are needed for evacuation and emergency response. We have a stark reminder from early 2025, when a long arch bridge in Isabela (northern Philippines) collapsed under an overweight truck, just weeks after it opened. Investigators noted the possibility of design issues and overloading, but one lesson was clear: even minor flaws can lead to major failures. In a disaster like a big quake, bridges will be under immense stress, and any hidden weakness could turn a vital bridge into a pile of rubble in seconds.
How can LiDAR help? By enabling regular, detailed health-checks of bridges without lengthy closures. LiDAR structural surveys can pick up tiny shifts or cracks in bridge components that human eyes might miss. In fact, survey-grade LiDAR is so precise it can produce millimeter-accurate 3D models of structures. Engineers can use these models to spot subtle signs of strain: a support pier that’s leaning a few millimeters, or a hairline crack growing over time in a critical beam. According to AB Surveying & Development (ABSD), a Philippine company pioneering LiDAR use, LiDAR can detect small cracks, shifts, and structural weaknesses before they become hazardous, by scanning bridges and comparing data over time. This means maintenance or reinforcement can be done proactively, before a collapse happens. Think of it as giving bridges a thorough medical check-up regularly, rather than waiting until they “feel sick.”
Equally important, LiDAR can map the terrain and riverbeds around bridges. Many bridge failures in quakes or storms are due to foundations giving way.
A great example of LiDAR’s power is the work done on the San Juanico Bridge – the iconic bridge connecting the islands of Samar and Leyte. ABSD performed a LiDAR survey of this longest bridge in the Philippines to assess its current condition and pinpoint any repairs needed. Remarkably, the 3D laser scan captured every crucial component of the bridge, down to the bolts in its steel framework. By examining this rich data, engineers can ensure even the smallest parts are intact and functioning. This level of insight is crucial for keeping such an important structure safe and open, especially with the constant wear and tear from traffic – and it’s exactly the kind of preventative measure that could prove life-saving when a massive quake strikes. A well-maintained, LiDAR-monitored bridge is far less likely to fail when the ground starts shaking.
Perhaps just as critical is what happens after an earthquake. With LiDAR, it can swiftly scan key bridges for damage in hours, whereas manual inspection might take days. Because LiDAR produces a detailed 3D model, engineers can immediately see if a bridge’s shape has subtly changed from the last scan – indicating potential structural damage – even if there’s no obvious crack to the naked eye.
This helps authorities decide beforehand which bridges are safe for use by rescue vehicles and which need to be closed or reinforced. In an earthquake’s aftermath, having even one extra bridge open for ambulances and supply trucks can save lives. LiDAR essentially gives us a fast-forward button on inspecting infrastructure, turning what could be a weeks-long process into something that can be done in a day or less, with better accuracy.
Safer Buildings Through Smart LiDAR Scanning
When the Big One hits, buildings will account for the majority of damage and casualties. Modern high-rises in Manila are engineered with quakes in mind, but thousands of older or smaller buildings from homes and schools to hospitals may not be up to current standards. Even some newer buildings might have construction flaws or have suffered wear over time. How can we make sure our buildings are structurally sound before a major quake, and assess them rapidly afterward? This is where LiDAR-based surveys and their digital 3D model’s shine.
Imagine an engineer trying to evaluate a building’s integrity. Traditionally, this means checking blueprints, looking for visible cracks in walls or columns, using handheld tools to measure tilts or alignment, and sometimes doing destructive tests (like chipping out a piece of concrete to see the rebar inside). It’s time-consuming and often impractical to do for every building of concern. LiDAR a detailed image of buildings. By scanning a structure from multiple angles outside and even indoors LiDAR can create a comprehensive 3D replica of the building. This replica isn’t just a pretty picture; it contains dimensional data accurate to within millimeters.
With such a model, engineers can virtually inspect parts of a building that are hard to access physically. For example, a slight sag in a floor or a subtle lean in a wall indicators of potential structural issues can be detected by measuring the point cloud. LiDAR can also map existing cracks in detail: their length, width, and propagation through a wall. In fact, it’s been demonstrated that a 3D laser scan can capture even fine cracks that a structure has developed over years. Having this baseline data is invaluable. If a building is scanned today and then re-scanned right after a future quake, comparing the two datasets will immediately highlight what’s changed perhaps new cracks or a shift in alignment – allowing a fast judgment on whether the building is safe or needs to be evacuated and repaired.
For instance, consider a high-rise office building in Makati. A LiDAR scan now might reveal that it’s missing some minor structural braces or has a slight uneven settlement on one side issues that can be corrected long before any quake. After an earthquake, another quick scan could reveal that while the building looks okay from outside, internally one corner column shortened by a few centimeters (a sign of potentially serious damage) something humans might not notice during the chaos. LiDAR’s precision and ability to digitally “freeze” the state of a structure in time makes it a powerful ally in structural health monitoring. As one industry expert noted, even minor surveying errors or overlooked structural weaknesses can lead to massive consequences in engineering. LiDAR minimizes those oversights by giving a thorough, data-rich view.
It’s worth emphasizing that LiDAR doesn’t work alone it provides the data that engineers and architects can use with their expertise. Increasingly, professionals feed LiDAR data into Building Information Models (BIM) or structural analysis software. They can simulate how a building would react to a strong quake using the accurate geometry from LiDAR scans. This helps identify weak points in advance and guide retrofitting efforts (like adding reinforcements or dampers). Think of it as creating a digital twin of the building that you can safely “stress test” on a computer, rather than finding out the hard way during a real earthquake.
LiDAR in Hazard Mapping for Disaster Planning in LGUs
Disaster risk reduction heavily relies on good maps. LiDAR has revolutionized hazard mapping in the Philippines over the past decade. One major initiative was the Department of Science and Technology’s Phil-LiDAR program, which used LiDAR to produce detailed 3D maps for flood and hazard modeling across the country. In fact, this program mapped 257 river basins nationwide to serve as the basis for planning disaster mitigation efforts. Similarly, ABSD had already surveyed multiple river basins for flood control projects. Why is this relevant to earthquakes? Because big quakes often trigger secondary disasters like dam failures, floods from broken levees, or landslides in the mountains that can dam rivers. Thanks to LiDAR-derived elevation models, local governments (LGUs) have accurate flood hazard maps and landslide susceptibility maps that can be consulted as part of earthquake preparedness.
For example, LiDAR-generated bare-earth models (DTMs) allow engineers to identify which neighborhoods are in low-lying areas that might turn into swamps if water lines break, or which hillsides could give way during intense shaking. LiDAR can also help map the trace of earthquake faults on the surface by revealing subtle terrain features (like fault scarps) hidden by vegetation. All this data feeds into risk assessments—essentially, who and what are in harm's way? With LiDAR, those answers come in high-definition.
By integrating LiDAR maps into tools like the government's HazardHunterPH system, an LGU or even an ordinary citizen can assess the hazards at any given location with a few clicks. For instance, Metro Manila’s comprehensive earthquake preparedness plan (the Valley Fault System Atlas) was built on detailed mapping of the fault line and identification of risk zones. LiDAR data complemented these efforts by providing accurate base maps of buildings and terrain. The bottom line is that LiDAR helps take the guesswork out of disaster planning. When you know exactly which areas will flood, which roads might be cut off, and where people can shelter safely, you can make a solid plan before disaster strikes.
Preserving Heritage: LiDAR Guards Our Past for the Future
Not all structures at risk are modern offices or utilitarian bridges. The Philippines, with its 300+ years of history, has many centuries-old churches, ancestral houses, and monuments that are irreplaceable treasures. These landmarks are especially vulnerable to a powerful quake many were built long before modern engineering, and have already endured countless typhoons, floods, and previous temblors. Saving lives is the top priority, but preserving our cultural heritage is also important. When the 2013 Bohol earthquake struck, for example, several historic churches crumbled to the ground, stunning communities who lost a piece of their identity. LiDAR is now playing a pivotal role in ensuring that even if the Big One strikes, our heritage need not be lost forever.
One way LiDAR helps is by creating detailed digital archives of these structures. Consider the case of San Nicolas de Tolentino Church in Ilocos Norte, a beautiful Baroque church first built in 1584. Recognizing its historical importance, the parish worked with a surveying team to perform a 3D laser as-built scanning of the entire church, inside and out. In just a few hours of scanning, intricate details of the structure were captured as a dense point cloud, including the ornate facade, the three-story bell tower, and even small features like carvings.
Impressively, the final 3D images displayed every feature, including cracks that the structure had developed over centuries. Those tiny cracks, which might be superficial or might hint at deeper weaknesses, are now documented. The digital model serves as a baseline if any crack grows larger in the future, conservators will know. Moreover, the scan data can be used as a basis for restorations, ensuring that any repairs honor the original design down to the millimeter.
Another example is the scanning of the “Monument of Outstanding Recollects”, a sculpture of six historical figures located at the Recoletos Formation Center in Quezon City. AB Surveying & Development scanned this monument using the same high-resolution laser technology, capturing its every curve and detail. The point here was to demonstrate that even for intricate art pieces, LiDAR can achieve an in-detail scan of the monument, with the resulting point cloud showing all the fine features. Now, imagine if (touch wood) an earthquake toppled or cracked such a monument – with the 3D data on hand, restoration teams could almost “rebuild” it digitally and physically with exact precision, or even 3D-print parts to replace fragments. In essence, LiDAR preserves a digital blueprint of cultural treasures, which is insurance against irreparable loss.
But beyond documentation, LiDAR is also useful for protective measures. For old churches like San Nicolas or, say, the San Agustin Church in Manila, a laser scan can reveal structural vulnerabilities perhaps a slight outward leaning of a heavy stone wall or weaknesses in the archways. Engineers can use this information to reinforce the structure (maybe adding nearly invisible supports or doing targeted repairs) to improve its earthquake resilience. Preservation isn’t just about recording how something looked; it’s also about keeping it standing if possible. And LiDAR gives conservation architects a powerful tool to plan these interventions with surgical accuracy, without having to physically probe every nook (which could be risky to the delicate structure).
Building a Resilient Future with LiDAR
Preparing for “The Big One” is a massive undertaking. It involves strict building codes, regular earthquake drills, efficient emergency services, and public education. No single tool or technology is a silver bullet. However, LiDAR surveying has emerged as one of the most promising technologies to boost our earthquake preparedness and resilience. Its ability to quickly produce precise 3D maps and models has applications at every stage: before, during, and after a disaster.
Before the earthquake: LiDAR helps identify vulnerabilities in our infrastructure (bridges, buildings, heritage sites) so they can be fixed in time. It creates digital backups of cultural treasures and important structures, ensuring nothing is “lost” even if physically damaged. It also aids urban planners in mapping out hazard areas – for instance, LiDAR mapping can reveal low-lying areas prone to liquefaction (when the ground turns to quicksand during shaking) so that heavy structures aren’t built there without extra reinforcement and allowing them to design evacuation plans early on. As the old saying goes, “An ounce of prevention is worth a pound of cure,” and LiDAR is all about that preventative data. As reported, regular LiDAR monitoring of bridges and structures can alert engineers to potential risks long before they turn into disasters.
After the earthquake: LiDAR’s role in detailed damage assessment and guiding reconstruction is invaluable. The data helps structural engineers decide what can be repaired and what needs to be torn down. It ensures that when we build back, we build back safer because we know exactly where the weak points were. It also provides transparency for communities: the 3D models can help explain why certain buildings are cordoned off or how much rebuilding needs to be done, keeping the public informed with visual evidence.
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