Legacy product - no abstract available

Legacy product - no abstract available

The Global Earthquake Model (GEM) is a public/private partnership to develop a global understanding of earthquake risk. Its purpose is to establish an independent, uniform standard for calculating and communicating earthquake risk, and to use this information to reduce earthquake losses worldwide. The 5-year program, which was formally incorporated in late 2008, has a budget of 35 million Euros, of which about 21 million Euros have been identified. The program will focus on three main modules: earthquake hazard, earthquake risk and socio-economic impact. In March 2009, Geoscience Australia hosted a kick-off meeting for GEM1, the first phase of the GEM program. GEM1 is aimed at developing an initial set of hazard and risk products as a proof of concept based on available tools, databases and information. Over 30 scientists and engineers from 18 countries participated in the workshop. At the first GEM Outreach meeting held in Hohenkammer, Germany in June 2009, there were approximately 120 participants from over 40 countries. This meeting was the first opportunity to explore the development of a series of regional initiatives that will be necessary to complement the development of core capability. I will present an overview of the development of GEM, including some of the main issues and priorities, as well the opportunities for and potential benefits of Australian participation.

Australian earthquake fault plane solutions have been compiled for all of Australia and contains the focal mechanisms of all known Australian earthquakes for which a mechanism has been determined. A total of 107 Focal Plane Solutions (FPS) are presented for 84 earthquakes in Australia and the surrounding region. The earthquakes are presented in chronological order and for each one the hypocentre, magnitude, focal plane solution and picture is given. Where available additional comments are included as is the data used to determine the mechanism (typically first motion data). This is the first time mechanisms for Australian eathquakes have been compiled into an atlas.

To achieve the RELACS Program's aim of improving the capabilities of the Rabaul Volcanological Observatory to locate and interpret volcano-related earthquake activity near Rabaul, a program of seismic field observation was undertaken in the Rabaul area by a consortium of institutions with significant experience in seismic work, viz AGSO, ANU, and the Universities of Hokkaido and Wisconsin. This Record describes post survey data processing of RELACS field data undertaken at the ANU, the University of Hokkaido and AGSO 1998-99. It also includes CDs of data files containing information on seismic recording stations, seismic shots, some earthquake locations, the arrival times of seismic waves, and seismic record files from stations in the international SUDS format.

This report contains information on earthquakes of Richter magnitude 3 or greater that were reported in the Australian region during 1990. It is the eleventh of an annual series compiled by the Australian Geological Survey Organisation (AGSO), using data from AGSO and various seismological agencies in Australia. Its purposes are to aid the study of earthquake risk in Australia, and to provide information on Australian and world earthquakes for scientists, engineers and the general public. The report has six main sections: Australian region earthquakes; Isoseismal maps; Network operations; Accelerograph data; Principal world earthquakes; and Monitoring of nuclear explosions.

Faults of the Lapstone Structural Complex (LSC) underlie 100 km, and perhaps as much as 160 km, of the eastern range front of the Blue Mountains, west of Sydney, Australia. More than a dozen major faults and monoclinal flexures have been mapped along its extent. Debate continues as to the age of formation of the ~400 m or more of relief relating to the LSC, with estimates ranging from Palaeozoic to Pliocene. The results of an investigation of Mountain Lagoon, a small basin bound on its eastern side by the Kurrajong Fault in the central part of the LSC, favour a predominantly pre-Neogene origin. Drilling on the eastern margin of the lagoon identified 15 m of fluvial, colluvial and lacustrine sediments, overlying shale bedrock. The sediments are trapped behind a sandstone barrier corresponding to the Kurrajong Fault. Dating of pollen grains preserved in sediments at the base of this sediment column suggest that the fault-angle depression began trapping sediment in the Early to Middle Miocene. Strongly heated Permo-Triassic gymnosperm pollen in the same strata provides circumstantial evidence that sediment accumulation post-dates the ca. 18.8 Ma emplacement of the nearby Green Scrub basalt. Our data indicate that only 15 m of the 130 m of throw across the Kurrajong Fault has occurred during the Neogene suggesting a predominantly erosional exhumation origin for current relief at the eastern edge of the Blue Mountains plateau. Sedimentation since the Late Pleistocene appears to have been controlled largely by climatic processes, with tectonism exerting little or no influence.

Stress Tensor reconstructions are presented for seven domains withinthe Australian crust based on formal inversion of four or more earthquake focal mechanisms in close geographic proximity. The data for inversion was sourced from a set of sixty-nine quality-ranked focal mechanisms forming part of the recently compiled AGSO focal mechanism database. When analysed in conjunction with in situ stress data held by the Australian Stress Map project, the new data makes possible for the first time a rigorous comparison of the Australian continental stress field at near-surface and seismogenic depths. A more complete picture of the character of the Australian intraplate stress field is thereby made available. The tensor data agrees well with in situ determinations in western, northern and far southeastern Australia suggesting that the continental stress field is homogeneous between shallow and seismogenic depth in these areas. Plate boundary forces are considered to be the dominant source of stress. In contrast, the results for the Sydney Basin and Flinders Ranges imply significant heterogeneity and influence by more localised sources of stress.

The Indonesia Earthquake Hazard Program (IEHP) is a four-year project aimed at enhancing the capacity of the Government of Indonesia (GoI) to undertake earthquake hazard and risk assessments. The IEHP is a joint collaboration between the Australia-Indonesia Facility for Disaster Reduction (AIFDR), the GoI, Indonesian Universities and Geoscience Australia.

Australia boasts arguably the richest Quaternary faulting record of all the world's SCR crust. Extensive consultation with the earth science community, and recent advances in digital elevation model coverage, have allowed the compilation of an inventory of over 200 landscape features consistent with fault scarps relating to Quaternary surface breaking earthquakes. This record, together with a growing database of palaeoseismicity data, permits analysis of the long term behaviour of SCR faults in different geologic settings. Details of variations in palaeoearthquake magnitude (including maximum magnitude), recurrence characteristics (given appropriate scaling relations and assumptions relating to landscape modification rates) and spatial relationships between scarps in different deforming regions are recoverable. A common characteristic across Australia appears to be the temporal clustering of large earthquakes. Active periods of earthquake activity comprising a finite number of large events are separated by much longer periods of seismic quiescence. This episodic behaviour poses problems for probabilistic seismic hazard assessments (PSHAs) in that it implies that recurrence of large earthquake events is not random (Poisson). The points critical to understanding the hazard posed by such faults, and modelling this hazard probabilistically, become: 1) is the SCR fault in question about to enter an active period, in the midst of an active period, or in a quiescent period, 2) how many large events might constitute an active period, and how many previous ruptures has the fault generated in its current active period (should it be in one), and 3) what is the 'average' recurrence interval in an active period, and what is the variability around this average. This 'average' can be incorporated statistically into PSHAs, and must be considered when palaeoearthquake catalogues are combined with historic records.