Advice to National Measurement Institute regarding update to the recognized-value standard of measurement for position, June 2011

Tropical cyclones present a significant hazard to countries situated in the warm tropical waters of the western Pacific. These severe storms are the most costly and the most common natural disaster to affect this region (World Bank, 2006). The hazards posed by these severe storms include the extreme winds, storm surge inundation, salt water intrusion into ground water supplies, and flooding and landslides caused by the intense rainfall. Despite the high vulnerability of the islands in this region, there have been relatively few previous studies attempting to quantify the hazard from tropical cyclones in this region (i.e. Shorten et al. 2003, Shorten et al. 2005, Terry 2007). Understanding this hazard is also vital for informing climate change adaptation options. This study aims to address the limited understanding of the extreme wind hazard in this region. The wind hazard from tropical cyclones is evaluated for the current climate and projections were made to assess how this hazard may change in the future. The analysis is performed using a combination of historical tracks and downscaled climate models with Geoscience Australia's Tropical Cyclone Risk Model. The work was funded as part of the Pacific Climate Change Science Program (PCCSP), which forms the science component of the International Climate Change Adaptation Initiative (ICCAI), an Australian government initiative designed to meet high priority climate change adaptation needs of vulnerable countries in our region. This study assesses the wind hazard for the fifteen PCCSP partner countries which include 14 islands located in the West Pacific as well as East Timor.

Tropical cyclones pose a significant threat to islands in the tropical western Pacific. The extreme winds from these severe storms can cause extensive damage to housing, infrastructure and food production. As part of the Pacific Climate Change Science Program (PCCSP), Geoscience Australia assessed the wind hazard posed by tropical cyclones for 14 islands in the western Pacific and East Timor. The wind hazard was assessed for both the current climate and for the future climate under the A2 SRES emission scenario. Wind hazard maps were generated using Geoscience Australia's Tropical Cyclone Risk Model (TCRM) that applies a statistical-parametric process to estimate return period wind speeds. To obtain a robust estimate of wind hazard from a short historical track record, TCRM produces several thousand years worth of tracks that are statistically similar to the input track dataset. The model then applies a parametric wind profile to these tracks and fits a Generalized Extreme Value distribution to the maximum wind speeds at each location. To estimate how the hazard may change in the future, tracks of Tropical Cyclone-Like Vortices (TCLVs) detected in dynamically downscaled global climate model are used as input into TCRM. This is performed for four downscaled global climate models for two twenty year periods centered on 1990 and 2090 under the A2 SRES emission scenario. This study provides the first detailed assessment of the current wind hazard for this region, despite the fact that these counties are both highly exposed and vulnerable to these severe storms. The hazard climate projections should be treated with caution due to known deficiencies in the global climate models and poor agreement between models of the hazard projections. However, keeping these limitations in mind, the results suggest that the wind hazard will decrease north of 20º latitude in the South Pacific by 2090.

Commonwealth Electoral Division of Hasluck - Landcover data with topographer underlay.

The development of the Indian Ocean Tsunami Warning and mitigation System (IOTWS) has occurred rapidly over the past few years and there are now a number of centres that perform tsunami modelling within the Indian Ocean, both for risk assessment and for the provision of forecasts and warnings. The aim of this work is to determine to what extent event-specific tsunami forecasts from different numerical forecast systems differ. This will have implications for the inter-operability of the IOTWS. Forecasts from eight separate tsunami forecast systems are considered. Eight hypothetical earthquake scenarios within the Indian Ocean and ten output points at a range of depths were defined. Each forecast centre provided, where possible, time series of sea-level elevation for each of the scenarios at each location. Comparison of the resulting time series shows that the main details of the tsunami forecast, such as arrival times and characteristics of the leading waves are similar. However, there is considerable variability in the value of the maximum amplitude (hmax) for each event and on average, the standard deviation of hmax is approximately 70% of the mean. This variability is likely due to differences in the implementations of the forecast systems, such as different numerical models, specification of initial conditions, bathymetry datasets, etc. The results suggest that it is possible that tsunami forecasts and advisories from different centres for a particular event may conflict with each other. This represents the range of uncertainty that exists in the real-time situation.

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Map compiled on request from AGS Native Title Case QUD6040/2001 Proclamation 1 See 2008/3111 for particulars.

Geoscience Australia (GA) is currently undertaking a process of revising the Australian National Earthquake Hazard Map using modern methods and an updated catalogue of Australian earthquakes. This map is a key component of Australia's earthquake loading standard, AS1170.4. Here we present an overview of work being undertaken within the GA Earthquake Hazard Project towards delivery of the next generation earthquake hazard map. Knowledge of the recurrence and magnitude (including maximum magnitude) of historic and pre-historic earthquakes is fundamental to any Probabilistic Seismic Hazard Assessment (PSHA). Palaeoseismological investigation of neotectonic features observed in the Australian landscape has contributed to the development of a Neotectonic Domains model which describes the variation in large intraplate earthquake recurrence behaviour across the country. Analysis of fault data from each domain suggests that maximum magnitude earthquakes of MW 7.0-7.5±0.2 can occur anywhere across the continent. In addition to gathering information on the pre-historic record, more rigorous statistical analyses of the spatial distribution of the historic catalogue are also being undertaken. Earthquake magnitudes in Australian catalogues were determined using disparate magnitude formulae, with many local magnitudes determined using Richter attenuation coefficients prior to about 1990. Consequently, efforts are underway to standardise magnitudes for specific regions and temporal periods, and to convert all earthquakes in the catalogue to moment magnitude. Finally, we will review the general procedure for updating the national earthquake hazard map, including consideration of Australian-specific ground-motion prediction equations. We will also examine the sensitivity of hazard estimates to the assumptions of certain model components in the hazard assessment.

Manila LiDAR Project 2011 Original Data Supply September 2011, provided by Fugro Spatial.

Map compiled on request from AGS Native Title Case QUD6040/2001 Proclamation 3 See 2008/3111 for particulars.