Earthquakes & Radiotherapy: Why Where We Build Matters

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This article was submitted by guest contributor, Dr. Yavuz Anacak, Professor of Radiation Oncology, Ege University (Izmir, Türkiye).

Professor Anacak published a paper in The Lancet Oncology, a first of its kind, evaluating the earthquake vulnerability of the radiotherapy centers in Türkiye.

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Earthquakes are not only a threat to homes and roads, but they can also disrupt lifesaving health services when hospitals and critical departments are damaged. In Türkiye, where major fault systems produce frequent high-magnitude events, the 2023 earthquakes displayed how quickly health-care capacity can be overwhelmed.

Radiotherapy is especially sensitive to interruptions: missed or delayed treatments can affect patient outcomes, and restarting services after a disaster can take weeks or months. This post summarizes key insights from a nationwide assessment of radiotherapy centers’ proximity to active faults, alongside practical steps to reduce the risk and protect continuity of cancer care.

Source: Balci-Topuz B. et al: Seismic vulnerability of Türkiye's radiotherapy centres: a nationwide analysis. The Lancet Oncology. Vol. 27, No. 3, p290–292, 2026.

Key points

Earthquakes may cause widespread damage to health facilities and major costs for recovery.
Radiotherapy bunkers (thick reinforced concrete) are structurally resilient—but non-bunker areas (clinics, waiting rooms, wards) can still fail and halt operations.
A nationwide mapping analysis found many radiotherapy centres are close to active faults with higher seismic exposure.
Distance to a fault is only one part of risk: local soil, liquefaction, landslides, rupture characteristics, and depth can considerably change impacts.
Risk reduction requires smart site selection, seismic microzonation, strong building regulations, retrofitting older facilities, and prepared staff/protocols.

Why radiotherapy continuity is a disaster-planning priority

Radiotherapy depends on specialized equipment (linear accelerators, brachytherapy units), stable utilities, trained teams, and radiation safe spaces for patients and staff. When an earthquake damages a hospital complex, even if the treatment bunker survives, services may still be suspended due to unsafe surrounding areas, disrupted workflows, or loss of supporting infrastructure.

What the 2023 earthquakes revealed

Reports from the 2023 events described significant damage across several hospital complexes that housed radiotherapy departments within the affected region. Importantly, radiotherapy bunkers largely remained structurally intact, highlighting the inherent robustness of radiation-shielded construction, however, operational continuity still suffered because adjacent spaces such as, outpatient clinics, waiting areas, wards, and general hospital systems were affected.

The nationwide vulnerability check: how close are centres to active faults?

The analysis mapped the coordinates of radiotherapy centres across Türkiye against the country’s digital active fault maps, then calculated each facility’s minimum distance to the nearest mapped fault category (for example, faults with evidence of recent activity). Proximity is not the whole story, but it is a practical first screening step: all else equal, facilities closer to active faults face higher likelihood of strong shaking, surface rupture impacts, and related infrastructure damage.

Main findings

A meaningful share of centres is located very close to active faults: some within 1 km, and many more within a few kilometers.
Only a limited number of centres are located far (tens of kilometers) from active faults.
Dense urban areas can concentrate exposure: for example, mapping around the Bay of Izmir shows multiple centres located within a very short distance of active faults.

Why “distance to a fault” is not the full risk picture

Earthquake impact is shaped by many local factors: soil type and basin effects, groundwater and liquefaction potential, slope stability and landslide risk, rupture direction, depth, and more. That’s why two earthquakes of similar magnitude can produce very different damage patterns across different cities, towns, and neighborhoods. A smart risk strategy combines fault proximity screening with detailed local hazard studies.

What can be done: siting, zoning, and microzonation

One of the most direct ways to reduce exposure is to avoid building critical facilities directly on or extremely near active faults. Some countries use Fault Avoidance Zones (FAZ), but setback distances vary, and more importantly, fault systems are complex: segmented structures, uncertain traces, and stress transfer between nearby faults mean risk cannot be captured by a single “X meters away” rule. This is where seismic microzonation becomes essential: detailed, local mapping of ground conditions and expected shaking/rupture hazards, which can support layered planning (core avoidance area, controlled-use zone, outer buffer) tailored to the function of a facility like a radiotherapy centre.

Resilience also depends on regulation and retrofitting

Robust building codes and enforcement matter—especially because radiotherapy services require costly construction and downtime is both clinically and economically expensive. Türkiye strengthened building standards after the 1999 Kocaeli earthquake, improving resilience in newer facilities. Yet many hospitals and some radiotherapy centres were built before those reforms. Retrofitting and targeted upgrades to older structures remain urgent, and regulators play a central role in setting standards, checking compliance, and identifying systemic weak points.

Preparedness: the “people and process” side of continuity

Even the best-designed building needs a readiness plan. Functional continuity depends on reliable communication systems, regular disaster drills, clear evacuation and shelter procedures, defined chains of responsibility, and support for staff well-being during prolonged crises. Teams that know the protocols and have practiced them, can restore services faster and reduce risk to patients at the moment it matters most.

Conclusion

In a country with significant seismic exposure, protecting radiotherapy is not just an engineering issue—it is a health-system resilience priority. The nationwide proximity screening highlights why siting decisions matter, while the 2023 earthquakes show that bunker strength alone cannot guarantee continuity. Combining smart location planning, microzonation-informed zoning, modern construction standards, retrofitting, and well-drilled preparedness can help keep oncology care running when communities need it most.

What we can do

Health authorities & regulators: require fault-proximity screening and microzonation evidence in approvals for new radiotherapy projects.
Hospital leadership: assess non-bunker areas and critical dependencies (power, IT, access routes) so radiotherapy can operate even if other wings are damaged.
Engineers & planners: use layered FAZ-style zoning and update facility master plans to avoid high-risk corridors where feasible.
Radiotherapy teams: run regular continuity drills (patient flow, equipment safety checks, evacuation, restart procedures) and keep “first 72 hours” protocols ready.
Everyone involved: treat radiotherapy continuity as an essential service. Plan redundancies and mutual-aid pathways across regions.

Dr. Yavuz Anacak is a Professor of Radiation Oncology at the Ege University in Izmir, Türkiye.

His main clinical and scientific research includes management of pediatric cancers, sarcomas, CNS tumors, lymphomas, brachytherapy applications and also nationwide planning for radiotherapy infrastructure and strategies to enhance radiotherapy capacity in low- and middle-income countries. He is currently chair of the Radiation Oncology Department of the Ege University and the past-president of the Turkish Society for Radiation Oncology. Prof. Anacak worked at the International Atomic Energy Agency (IAEA) for several research and educational projects and missions worldwide. He is a member of the ESTRO, International Society for Pediatric Oncology (SIOP), Pediatric Radiation Oncology Society (PROS) and Turkish Pediatric Oncology Society (TPOG).