Australia’s buildings weren’t historically designed for significant earthquake loads. The continent sits on a stable tectonic plate experiencing fewer and gentler earthquakes than Pacific neighbours. But recent moderate earthquakes in Melbourne, Newcastle, and other cities revealed vulnerabilities in existing structures. Structural engineers are researching how to improve earthquake resilience in new buildings and retrofit existing structures without prohibitive costs.

Reassessing Seismic Risk

Australia experiences far fewer damaging earthquakes than Japan, New Zealand, or California. But intraplate earthquakes—those occurring within tectonic plates rather than at boundaries—can still cause significant damage. The 2021 Melbourne earthquake was moderate by global standards but caused widespread minor damage and exposed vulnerability in buildings that weren’t designed for such shaking.

Updated seismic hazard maps developed by Geoscience Australia show higher earthquake probabilities than previously estimated in some regions. Southeast Australia, Adelaide, and parts of Western Australia face modest but non-negligible earthquake risk. This has prompted reconsideration of building code requirements for these areas.

The challenge is calibrating requirements appropriately. Designing all buildings to withstand major earthquakes would be extremely expensive and arguably wasteful given low probability of severe shaking. But ignoring risk entirely leaves communities vulnerable. Finding appropriate middle ground requires balancing safety, cost, and risk tolerance.

Existing Building Vulnerabilities

Many Australian buildings were constructed before modern seismic codes existed or in regions where codes required minimal earthquake resistance. Unreinforced masonry buildings—common in older urban areas—are particularly vulnerable. Brick walls without reinforcement can collapse catastrophically during moderate shaking.

The University of Melbourne’s infrastructure engineering group has conducted surveys of building stock in high-risk areas, identifying vulnerable building types and estimating potential damage from scenario earthquakes. Results are sobering: a magnitude 6 earthquake near Melbourne or Sydney would cause billions in damage and potentially dozens of fatalities from structural failures.

Tall buildings built to older standards face different risks. While generally more robust than unreinforced masonry, older concrete and steel structures may lack ductility—the ability to deform without collapse—that modern seismic designs prioritise. During strong shaking, these buildings could suffer structural damage even if they don’t collapse.

Modern Seismic Design Principles

Contemporary seismic building design aims to prevent collapse during major earthquakes while accepting that damage may occur. The philosophy is life safety rather than preventing all damage. Buildings should remain standing long enough for occupants to evacuate, even if the structure is damaged beyond repair.

This is achieved through ductile design—structures that bend and deform rather than break. Steel reinforcing in concrete, moment-resisting frames, and shear walls all contribute to ductility. Australian standards increasingly adopt international seismic design practices, though adapted for lower seismic hazards than earthquake-prone regions face.

Base isolation—mounting buildings on flexible bearings that absorb earthquake motion—is used for critical facilities like hospitals. The technology is proven but expensive, limiting application to buildings where continued operation during and after earthquakes is essential. For most buildings, conventional seismic design without base isolation is more cost-effective.

Retrofitting Existing Buildings

Retrofitting vulnerable buildings poses enormous challenges. Techniques exist—adding steel frames, strengthening walls, installing damping systems—but costs often approach building replacement. Determining which buildings warrant retrofit investment requires assessing risk, occupancy, and heritage value.

UNSW’s engineering faculty has tested low-cost retrofit approaches for common building types. Carbon fibre wrapping for masonry walls and steel bracing for timber frames can substantially improve earthquake resistance at costs that might be economically feasible. But even these “economical” approaches cost tens of thousands per building.

Mandating retrofits raises equity concerns. Building owners—many of modest means—face sudden requirements to spend substantial sums improving earthquake resistance against risks they’ve safely ignored for decades. Government subsidies could ease burdens but would cost billions for comprehensive programs.

Performance-Based Design Evolution

Traditional prescriptive codes specify construction requirements: wall thickness, reinforcing quantities, connection details. Performance-based approaches instead specify desired performance—maximum allowable damage, continued functionality—and allow engineers flexibility in achieving those outcomes through any suitable design approach.

Performance-based design enables innovation and optimization that prescriptive codes constrain. But it requires sophisticated engineering analysis that smaller firms may lack capacity for. Australian building codes are gradually incorporating performance-based options while retaining prescriptive paths for simpler projects.

Swinburne University researchers are developing simplified performance-based design tools that smaller engineering firms can use. Their software allows engineers to evaluate seismic performance without conducting complex simulations that require specialist expertise. Democratising access to advanced analysis methods could improve seismic design without requiring all engineers to become specialists.

Material Innovation Research

Advanced materials offer potential improvements in seismic performance. High-performance concrete, shape-memory alloys, and fibre-reinforced polymers all provide properties useful for earthquake-resistant structures.

Monash University’s civil engineering department is investigating ultra-high-performance concrete that achieves strength and ductility impossible with conventional concrete. The material could enable thinner structural elements with better earthquake performance. But costs currently limit application to specialised uses rather than routine construction.

Shape-memory alloys—metals that return to original shape after deformation—could create self-centering structures that return to vertical after earthquake shaking. Research prototypes demonstrate the concept works, but materials costs and connection details requiring further development prevent widespread adoption.

Non-Structural Components

Building contents and architectural elements—ceilings, cladding, services—can cause injuries and damage during earthquakes even when structural systems perform well. Falling ceiling tiles, toppling bookcases, or failing cladding pose immediate dangers to occupants.

Research at University of Canterbury (NZ) in partnership with Australian institutions is developing design guidelines for non-structural components. Recommendations cover bracing, anchoring, and clearances that prevent dangerous failures. Implementation is gradually occurring in new construction, though retrofitting non-structural improvements in existing buildings receives less attention than structural issues.

Post-Earthquake Building Assessment

After earthquakes, rapid building assessments determine which structures are safe to occupy and which require evacuation. Developing assessment procedures that enable quick, accurate safety determinations is essential for emergency response.

Engineers Australia has developed rapid assessment protocols based on international practice adapted for Australian conditions. Training programs prepare engineers to conduct these assessments, though practical experience is limited given infrequent damaging earthquakes. Simulation exercises provide some preparation but can’t fully replicate post-earthquake conditions.

Digital tools using building information models and structural analysis are being researched to assist post-earthquake assessment. Engineers could input observed damage patterns and receive preliminary safety assessments more quickly than manual structural analysis would allow. The technology is promising but requires further validation before operational deployment.

Insurance and Financial Resilience

Earthquake insurance is available but not universally held by Australian property owners given historically low risk. After significant earthquakes, uninsured owners face repair costs that may exceed property values. This creates social and financial disruptions beyond immediate physical damage.

Research at University of Melbourne’s Centre for Disaster Management examines financial mechanisms for earthquake resilience. Parametric insurance—paying out based on earthquake magnitude rather than assessed damage—could speed recovery. Government-backed reinsurance schemes could make coverage more affordable. Implementing these requires policy changes beyond engineering solutions alone.

Building Code Evolution

Australian building codes evolve gradually through Standards Australia processes involving engineers, regulators, and industry. Significant changes require years of consensus-building and often don’t occur until after disasters demonstrate weaknesses in existing practices.

Recent Melbourne earthquakes have accelerated discussions about seismic provisions. Updates to loading standards are in development, likely requiring stronger seismic design in moderate-risk regions. Implementation will be gradual—existing buildings aren’t affected, new buildings will meet updated standards over time.

Some engineers argue changes should be more aggressive given evidence of earthquake risk. Others contend that catastrophic failure risk remains low enough that expensive requirements aren’t justified. Balancing these perspectives in code development is contentious but necessary for workable standards.

International Knowledge Transfer

Australia can’t rely solely on domestic experience given limited earthquake occurrences. Learning from New Zealand, Japan, California, and other earthquake-prone regions provides valuable knowledge. But direct transfer is complicated by different construction practices, materials, and seismic hazards.

Research collaborations enable Australian engineers to participate in international projects and access expertise beyond domestic capabilities. Graduate students studying overseas in earthquake engineering programs return with knowledge and connections that strengthen Australian capabilities. Maintaining these international links is essential for sustaining expertise despite limited local practical application.

Realistic Progress Path

Comprehensive earthquake resilience in Australian building stock won’t happen quickly or cheaply. Realistic expectations involve gradual improvements: new buildings designed better, highest-risk existing buildings eventually retrofitted or replaced, emergency response capabilities enhanced, and public awareness increased.

Progress requires sustained commitment beyond media attention following earthquakes. When years pass without events, maintaining focus on earthquake resilience is politically challenging. But research, code development, and gradual implementation continue even when earthquake risk isn’t headline news.

Australian structural engineering research contributes to safer buildings through better design methods, innovative materials, and improved understanding of seismic behaviour. Whether this knowledge translates to meaningful risk reduction depends on implementation through building codes, retrofit programs, and community awareness—all extending well beyond research capabilities alone.