Earthquakes occur without warning and human mobility during strong shaking is difficult. This has implications for casualty outcomes from such rapid onset events. Unreinforced masonry (URM) in particular presents a great risk in the high pedestrian exposure precincts of major cities. Surveys of major Australian cities have indicated that almost half of the central business district (CBD) buildings by number are of older URM construction and have elements that could fall onto pedestrians in a major shake. With a focus on the greater CBD of Melbourne, this risk and mitigation options for it have been studied. In a case study undertaken as part of the Bushfire and Natural Hazards CRC (BNHCRC), the casualties, damage and broader economic consequences of a major earthquake in central Melbourne have been modelled. This research directly utilised BNHCRC vulnerability research on URM by the authors and separate work by Geoscience Australia on modelling human exposure in a major business precinct. Through a virtual retrofit of the high risk URM buildings the benefits of retrofit were demonstrated. In particular, the prioritising of areas of high human exposure in a manner similar to that being used in New Zealand was found to achieve greater reductions of injuries. Abstract submitted to / presented at the 2022 Australian Earthquake Engineering Society (https://aees.org.au/aees-conference-2022/)

In Australia there is a lack of retrospective building regulation to address earthquake prone buildings within communities. The commitment of funds to retrofit high risk buildings either by property owners for by government requires decisions to commit constrained resources for this purpose. Engineers are able to communicate the physical solutions to address these buildings but may be less able to articulate the risk reduction proposition to property owners who may reside or operate a business in the building. Further, emergency managers and government policy makers may not understand the broader issues and benefits of targeted intervention. This paper focusses on unreinforced masonry and describes a program of work that has translated earthquake hazard and engineering vulnerability into a range of communication products. Learnings from the application of masonry mitigation research in two case study communities are presented along with their translation into a range of communication products tailored to a range of decision makers and users. The range of benefits considered are broader than damage avoidance, extending to emergency management logistics, economic activity and avoiding losing heritage value in communities. It also describes forward initiatives to integrate earthquake retrofit into broader resilience building interventions that address other natural hazard deficiencies. Abstract submitted to/presented at the 2022 Australian Earthquake Engineering Society (AEES) Conference (https://aees.org.au/aees-conference-2022/).

<div>We performed an earthquake risk assessment of seven smaller communities across the Yilgarn of Western Australia (WA): Northam, Merredin, Cunderdin, Kellerberrin, Wundowie, Meckering, and Tammin. This was done as a part of activities of a project entitled “Risk Assessment and Mitigation Study for Earthquakes in the Yilgarn” which, in addition to assessing risk posed to buildings by earthquakes, has a focus on understanding critical infrastructure system risk in the Yilgarn region. We modelled earthquake hazard based on the 2018 National Seismic Hazard Assessment and Geoscience Australia’s seismic site conditions map for Australia. Building exposure data was compiled by a desktop survey using available aerial imagery, purpose captured GoPro streetview type imagery and publicly available real estate information to record building attributes. We used Geoscience Australia’s current vulnerability functions which include a range of models collaboratively developed for high-risk unreinforced masonry buildings. The estimated average annualised loss ratios for the communities range from 0.008% to 0.027%, with the highest being for Kellerberrin, and the lowest being for Wundowie. We combined the damage related risk with the Australian Disaster Resilience Index to identify communities of high risk and lower resilience. Six earthquake scenario events were modelled along with the risk and impact reductions achieved through a virtual retrofit of old URM buildings in the communities. In this paper the outcomes of this research are presented and discussed in a national context.&nbsp;</div> Presented at the 2023 Australian Earthquake Engineering Society (AEES) National Conference