Explore important concepts about groundwater using this comprehensive teaching resource. This mini unit includes case studies of Australian groundwater topics, First Nations Australian perspectives about water use and groundwater are also included. This mini unit included four files - the guide, 2 x student activities and a kml file. The guide includes educator tips as well as answers to the student activities. Suitable for upper primary to lower secondary students.

<div>Sander Geophysics Limited (SGL) conducted a fixed-wing high resolution gravimetric survey in the East Kimberley area of the state of Western Australia for Geoscience Australia. A total of 37,806 line kilometres of airborne gravity data were acquired using </div><div>SGL’s airborne gravity system, Airborne Inertially Referenced Gravimeter (AIRGrav). The survey was funded by the Department of Mines, Industry Regulation and Safety (DMIRS) Western Australia, and managed by Geoscience Australia.</div><div><br></div><div>The data were peer reviewed by airborne gravity expert Dr Mark Dransfield contracted by Geoscience Australia.</div><div><br></div><div>The data from this survey were released by the Geological Survey of Western Australia and can be downloaded from MAGIX under reference 71156.</div><div><br></div><div><strong>Survey details</strong></div><div>Survey Name: East Kimberley Airborne Gravity Survey 2016</div><div>State/Territory: Western Australia</div><div>Datasets Acquired: Airborne gravity, </div><div>Geoscience Australia Project Number: P1289</div><div>Acquisition Start Date: 08 October 2016</div><div>Acquisition End Date: 03 December 2016</div><div>Flight line spacing: 2,500m</div><div>Flight line direction: East-West</div><div>Tie line spacing: 25,000m</div><div>Tie line direction: North-South</div><div>Total distance flown: 37,806 line km</div><div>Nominal terrain clearance (above ground level): 160m</div><div>Aircraft type: Fixed wing Cessna Grand Caravan 208B</div><div>Data Acquisition: Sander Geophysics Limited</div><div>Project Management: Geoscience Australia</div><div>Quality Control: Geoscience Australia</div><div>Dataset Ownership: Western Australia Department of Mines, Industry Regulation and Safety, and Geoscience Australia</div><div><br></div><div><strong>Files included in this download</strong></div><div><br></div><div><strong>1. Point-located data / line data</strong> </div><div>Data in ASEG GDF2 format, with accompanying description and definition files </div><div>P1289_grav.dat – survey data</div><div>P1289_grav.dfn – survey data definition</div><div>P1289_grav.met – survey metadata</div><div><br></div><div><strong>2. Grids - 7 grid files</strong></div><div>Datum:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;GDA94</div><div>Projection:&nbsp;&nbsp;MGA 52 </div><div>Grid cell size:&nbsp;500m</div><div>Formats:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;General eXchange Format (.gxf) and ERMapper (.ers) format.</div><div><br></div><div>Grid name Units Description</div><div>- GRVFAL2500M&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; µms-2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Free air gravity, 2500m half-wavelength spatial filter</div><div>- FVDFAL2500M&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;Eotvos&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;First vertical derivative of free air gravity, 2500m half-wavelength spatial filter</div><div>- GRVBGL2500M_267&nbsp;&nbsp;µms-2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Full Bouguer gravity, 2500m half-wavelength spatial filter, 2670 kg/m3 density</div><div>- FVDBGL2500M_267&nbsp;&nbsp;Eotvos&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;First vertical derivative of full Bouguer gravity, 2500m half-wavelength spatial filter, 2670 kg/m3 density</div><div>- GRVISO2500M_267&nbsp;&nbsp;&nbsp;µms-2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Isostatic residual gravity, 2500m half-wavelength spatial filter, 2670 kg/m3 density</div><div>- FVDISO2500M_267&nbsp;&nbsp;&nbsp;Eotvos&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;First vertical derivative of isostatic residual gravity, 2500m half-wavelength spatial filter, 2670 kg/m3 density</div><div>- BAREEARTH&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; m&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Bare earth terrain (above GDA94 Ellipsoid)</div><div><br></div><div><strong>3. Reports</strong> </div><div>- Delivery Information from contractor: Delivery Information - East Kimberley AIRGrav.pdf</div><div>- Final technical report from the contractor: East Kimberley 2016 TR-842-002.pdf </div><div>- Quality control report: East Kimberley 2016 QC report.pdf </div><div><br></div>

Papua New Guinea (PNG) lies in a belt of intense tectonic activity that experiences high levels of seismicity. Although this seismicity poses significant risks to society, the Building Code of PNG and its underpinning seismic loading requirements have not been revised since 1982. This study aims to partially address this gap by updating the seismic zoning map on which the earthquake loading component of the building code is based. We performed a new probabilistic seismic hazard assessment for PNG using the OpenQuake software developed by the Global Earthquake Model Foundation (Pagani et al. 2014). Among other enhancements, for the first time together with background sources, individual fault sources are implemented to represent active major and microplate boundaries in the region to better constrain the earthquake-rate and seismic-source models. The seismic-source model also models intraslab, Wadati–Benioff zone seismicity in a more realistic way using a continuous slab volume to constrain the finite ruptures of such events. The results suggest a high level of hazard in the coastal areas of the Huon Peninsula and the New Britain – Bougainville region, and a relatively low level of hazard in the southwestern part of mainland PNG. In comparison with the seismic zonation map in the current design standard, it can be noted that the spatial distribution of seismic hazard used for building design does not match the bedrock hazard distribution of this study. In particular, the high seismic hazard of the Huon Peninsula in the revised assessment is not captured in the current building code of PNG. <b>Citation:</b> Ghasemi, H., Cummins, P., Weatherill, G. <i>et al.</i> Seismotectonic model and probabilistic seismic hazard assessment for Papua New Guinea. <i>Bull Earthquake Eng, </i><b>18</b>, 6571–6605 (2020). https://doi.org/10.1007/s10518-020-00966-1

Seismic hazard models, commonly produced through probabilistic seismic hazard analysis, are used to establish earthquake loading requirements for the built environment. However, there is considerable uncertainty in developing seismic hazard models, which require assumptions on seismicity rates and ground-motion models (GMMs) based on the best evidence available to hazard analysts. This paper explores several area-based tests of long-term seismic hazard forecasts for the Australian continent. ShakeMaps are calculated for all earthquakes of MW 4.25 and greater within approximately 200 km of the Australian coastline using the observed seismicity in the past 50 years (1970-2019). A “composite ShakeMap” is generated that extracts the maximum peak ground acceleration “observed” in this 50-year period for any site within the continent. The fractional exceedance area of this composite map is compared with four generations of Australian seismic hazard maps for a 10% probability of exceedance in 50 years (~1/500 annual exceedance probability) developed since 1990. In general, all these seismic hazard models appear to be conservative relative to the observed ground motions that are estimated to have occurred in the last 50 years. To explore aspects of possible prejudice in this study, the variability in ground-motion exceedance was explored using the Next Generation Attenuation-East GMMs developed for the central and eastern United States. The sensitivity of these results is also tested with the interjection of a rare scenario earthquake with an expected regional recurrence of approximately 5,000 - 10,000 years. While these analyses do not provide a robust assessment of the performance of the candidate seismic hazard for any given location, they do provide—to the first order—a guide to the performance of the respective maps at a continental scale. This paper was presented at the Australian Earthquake Engineering Society 2021 Virtual Conference, Nov 25 – 26.

A database of recordings from moderate-to-large magnitude earthquakes is compiled for earthquakes in western and central Australia. Data are mainly recorded by Australian National Seismograph Network (ANSN), complemented with data from temporary deployments, and covering the period of 1990 to 2019. The dataset currently contains 1497 earthquake recordings from 164 earthquakes with magnitudes from MW 2.5 to 6.1, and hypocentral distances up to 1500 km. The time-series data are consistently processed to correct for the instrument response and to reduce the effect of background noise. A range of ground-motion parameters in the time and frequency domains are calculated and stored in the database. Numerous near-source recordings exceed peak accelerations of 0.10 g and range up to 0.66 g, while the maximum peak velocity of the dataset exceeds 27 cm/s. In addition to its utility for engineering design, the dataset compiled herein will improve characterisation of ground-motion attenuation in the region and will provide an excellent supplement to ground-motion datasets collected in analogue seismotectonic regions worldwide. This paper was presented at the Australian Earthquake Engineering Society 2021 Virtual Conference, Nov 25 – 26.

Public concerns have been raised about the potential for induced seismicity as state and territory governments lift moratoriums on hydraulic stimulation activities for the exploration and extraction of unconventional hydrocarbons. The Scientific Inquiry into Hydraulic Fracturing in the Northern Territory articulated the need for a traffic-light system “to minimise the risk of occurrence of seismic events during hydraulic fracturing operations” within the Beetaloo Sub-basin. A temporary seismic network (Phase 1) was deployed in late 2019 to monitor baseline seismic activity in the basin. Based on the data analysed herein (November 2019 – April 2021), no seismic events were identified within the area of interest suggesting that the Beetaloo Sub-basin is largely aseismic. Observations to date indicate that there is potential to identify events smaller than ML=1.5 within the basin. The recent installation of ten semi-permanent stations for continuous real-time monitoring will contribute to ongoing baseline monitoring efforts and support the implementation of an induced seismicity traffic-light system. The outcome of this study will be used to build knowledge about potential human-induced seismic activity in the region that may be associated with unconventional hydrocarbon recovery. This paper was presented at the Australian Earthquake Engineering Society 2021 Virtual Conference, Nov 25 – 26.

Here we undertake a statistical analysis of local magnitudes (ML) calculated using the two real-time earthquake monitoring software platforms use by Geoscience Australia (GA) since 2005, Antelope and Seiscomp. We examine a database of just over 10 years duration, during a period in which both systems were in operation and over 4000 earthquakes were located and magnitudes estimated. We examine the consistency of both single-station and network ML estimates of both systems, with a view toward determining guidelines for combining them into a single catalogue, as well as for determining best practice in the for the estimation of local magnitudes for regions of sparse seismic networks. Once this guidance has been developed, it is the intention of GA to re-process magnitudes for all earthquakes using a consistent approach where digital data are available and can be integrated within the currently-used SeisComP system. This paper was presented at the Australian Earthquake Engineering Society 2021 Virtual Conference, Nov 25 – 26.

The 22 September 2021 (AEST) moment magnitude MW 5.9 Woods Point earthquake was the largest in the state of Victoria’s recorded history. The ground motions were felt throughout the state of Victoria and into neighbouring states New South Wales and South Australia. Minor damage was reported in the city of Melbourne and in some regional towns close to the epicentre. This event was captured on many high-quality recorders from multiple sources, including private, university, and public stations. These recordings provide a rare opportunity to test the validity of some ground motion models thought to be applicable to the southeast region of Australia. This paper presents spectral acceleration and attenuation comparisons of the Woods Point earthquake event to some ground motion models. The results of this paper provide further evidence that the attenuation characteristics of southeastern Australia may be similar to that in central and eastern United States, particularly at shorter distances to the epicentre. This paper was presented at the Australian Earthquake Engineering Society 2021 Virtual Conference, Nov 25 – 26.

<div>In response to the acquisition of national-scale airborne electromagnetic surveys and the development of a national depth estimates database, a new workflow has been established to interpret airborne electromagnetic conductivity sections. This workflow allows for high quantities of high quality interpretation-specific metadata to be attributed to each interpretation line or point. The conductivity sections are interpreted in 2D space, and are registered in 3D space using code developed at Geoscience Australia. This code also verifies stratigraphic unit information against the national Australian Stratigraphic Units Database, and extracts interpretation geometry and geological data, such as depth estimates compiled in the Estimates of Geological and Geophysical Surfaces database. Interpretations made using this workflow are spatially consistent and contain large amounts of useful stratigraphic unit information. These interpretations are made freely-accessible as 1) text files and 3D objects through an electronic catalogue, 2) as point data through a point database accessible via a data portal, and 3) available for 3D visualisation and interrogation through a 3D data portal. These precompetitive data support the construction of national 3D geological architecture models, including cover and basement surface models, and resource prospectivity models. These models are in turn used to inform academia, industry and governments on decision-making, land use, environmental management, hazard mapping, and resource exploration.</div>

The fundamental geological framework of the concealed Paleoproterozoic East Tennant area of northern Australia is very poorly understood, despite its relatively thin veneer of Phanerozoic cover and its position along strike from significant Au–Cu–Bi mineralisation of the Tennant Creek mining district within the outcropping Warramunga Province. We present 18 new U–Pb dates, obtained via Sensitive High Resolution Ion Micro Probe (SHRIMP), constraining the geological evolution of predominantly Paleoproterozoic metasedimentary and igneous rocks intersected by 10 stratigraphic holes drilled in the East Tennant area. The oldest rocks identified in the East Tennant area are two metasedimentary units with maximum depositional ages of ca. 1970 Ma and ca. 1895 Ma respectively, plus ca. 1870 Ma metagranitic gneiss. These units, which are unknown in the nearby Murphy Province and outcropping Warramunga Province, underlie widespread metasedimentary rocks of the Alroy Formation, which yield maximum depositional ages of 1873–1864 Ma. While parts of this unit appear to be correlative with the ca. 1860 Ma Warramunga Formation of the Warramunga Province, our data suggest that the bulk of the Alroy Formation in the East Tennant area is slightly older, reflecting widespread sedimentation at ca. 1870 Ma. Throughout the East Tennant area, the Alroy Formation was intruded by voluminous 1854–1845 Ma granites, contemporaneous with similar felsic magmatism in the outcropping Warramunga Province (Tennant Creek Supersuite) and Murphy Province (Nicholson Granite Complex). In contrast with the outcropping Warramunga Province, supracrustal rocks equivalent to the 1845–1810 Ma Ooradidgee Group are rare in the East Tennant area. Detrital zircon data from younger sedimentary successions corroborate seismic evidence that at least some of the thick sedimentary sequences intersected along the southern margin of the recently defined Brunette Downs rift corridor are possible age equivalents of the ca. 1670–1600 Ma Isa Superbasin. Our new results strengthen ca. 1870–1860 Ma stratigraphic and ca. 1850 Ma tectono-magmatic affinities between the East Tennant area, the Murphy Province, and the mineralised Warramunga Province around Tennant Creek, with important implications for mineral prospectivity of the East Tennant area. Appeared in Precambrian Research Volume 383, December 2022.