Clive Collins

The crust-mantle boundary is defined seismologically by the Mohorovicic discontinuity (or Moho), where the velocity of seismic waves increases from typical crustal values to typical mantle values. The depth of the Moho beneath Australia has been mapped using all available seismic data in order to study the crustal thickness patterns and their relat...

The Bureau of Mineral Resources (BMR) undertook a regional marine seismic survey of the Gippsland Basin in 1988?89. During this survey, recording stations were deployed onshore by the BMR and the Department of Earth Sciences, Monash University, to record long-offset wide-angle reflection and refraction data from the standard marine seismic reflecti...

2004 NZSEE Conference ABSTRACT: Australia has a low rate of modern seismicity compared to plate margin regions, and a short historical record of earthquakes. These factors combined manifest as significant uncertainty in the Australian earthquake hazard map. One approach to address the problem of sparse historic seismicity in intraplate regions like...

The seismological definition of the crust-mantle boundary is based on the identification of the boundary which separates low seismic P-wave velocities (less than about 7.8 km/s) associated with predominantly crustal rock types, from higher velocities (greater than 7.8 km/s) usually associated with mantle rock types, ie the Moho discontinuity. The M...

The historical record of seismicity in Australia is too short (less than 150 years) to confidently define seismic source zones, particularly the recurrence rates for large, potentially damaging earthquakes, and this leads to uncertainty in hazard assessments. One way to extend this record is to search for evidence of earthquakes in the landscape, i...

The wheatbelt region of southwest Western Australia is an area of elevated intraplate seismicity. The seismicity is highly clustered, with 80 active clusters identified over the last 20 years. This report reviews the seismicity between July 2022 and June 2024, which includes continuing seismicity from the Arthur River region, and a damaging magnitu...

A seismic sequence near Arthur River, in the southwest of Western Australia, began in January 2022 and has continued into late 2023. Since September 2022 the seismicity has continued to be monitored, but by a reduced network of field stations. Locations of the newer events are presented here, plus relocations of some of the better recorded events o...

Previous reports on southwest Western Australia (SWA) seismicity have identified 80 cluster locations, mostly from activity in the last 10 years. Earthquakes in the region in 2021-22 are reviewed here and allocated to cluster locations where considered appropriate. Most of the seismicity can be assigned to one of 18 cluster locations considered act...

A significant series of earthquakes occurred near Burakin in the northern WA wheat belt between September 2001 and June 2002, including three ML 5 events. Geoscience Australia (GA) deployed up to 15 field seismographs in the area at various times in that period to provide better earthquake locations, but a detailed review of the data has not been p...

An ML 5.7 earthquake occurred NW of Rocky Gully, in southern WA on 16 Sep 2018 and formed a N-S trending surface rupture, visible intermittently over about 5 km. The event was followed by a ML 5.3 event about 7 weeks later. Geoscience Australia (GA) installed 5 field stations 4 days after the main event, and recorded about 900 mostly small aftersho...

Clustered intra plate seismicity in south west Australia

Although the time-averaged shear-wave velocity down to 30 m depth (V-S30) can be a proxy for estimating earthquake ground-motion amplification, significant controversy exists about its limitations when used as a single parameter for the prediction of amplification. To examine this question in absence of relevant strong-motion records, we use a rang...

The Cadell Fault, found in stable continental region (SCR) crust in southeastern Australia, provides a record of temporally clustered morphogenic earthquakes spanning much of the Cenozoic. The slip rate, averaged over perhaps as many as five complete seismic cycles in the period 70–20 ka, is c. 0.4–0.5 mm a ⁻¹ , compared with an average rate of c....

In stable continental regions (SCRs), the process of probabilistic seismic- hazard assessment (PSHA) remains a scientific and technical challenge. In producing a new national hazard model for Australia, we developed several innovative techniques to address these challenges. The Australian seismic catalog is heterogeneous due to the variability bet...

Introduction Australia is classified as a Stable Continental Region (SCR) in terms of its plate tectonic setting and seismicity (Johnston et al. 1994). While such settings produce only approximately 0.2% of the world's seismic moment release, large and potentially damaging earthquakes are not uncommon (e.g. Crone et al. 1997). In the last four deca...

Since 2004 more than 7000 km of full-crustal reflection profiles have been collected across Australia to give a total of more than 11 000 km, providing valuable new constraints on crustal structure. A further set of hitherto unexploited results comes from 150 receiver functions distributed across the continent, mostly from portable receiver sites....

This paper discusses two of the key inputs used to produce the draft National Earthquake Hazard Map for Australia: 1) the earthquake catalogue and 2) the ground-motion prediction equations (GMPEs). The composite catalogue used draws upon information from three key catalogues for Australian and regional earthquakes; a catalogue of Australian earthqu...

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 Earthquak...

Australia’s rich neotectonic record provides an opportunity to better understand the characteristics of seismogenic intraplate deformation, both at the scale of a single fault and at the scale of the entire continent. Over the last decade knowledge of Australian intraplate faults has advanced significantly. Herein we review this knowledge and propo...

The inventory of over 200 fault scarps captured in GA's Australian neotectonics database, comprising both probable and proven palaeo-earthquake sources, has been used to produce preliminary estimates of the maximum credible magnitude earthquake (Mmax) across the Stable Continental Regions (SCRs) of Australia. This was done by first grouping the sca...

In July of 2006 a seismic swarm struck near the Sulu volcanic range on the north coast of central New Britain Island, in Papua New Guinea. In the global Centroid Moment Tensor (CMT) catalog (www.globalcmt.org) a total of eighteen earthquakes were large enough for CMT solutions to be determined. The magnitudes of earthquakes with CMT solutions range...

In July 2006, unusual earthquake activity commenced in the Sulu Range area, Central New Britain, Papua New Guinea, accompanied by vigorous activity in neighbouring hot springs. This region has not been active in historic times, so these events caused alarm and resulted in evacuation of the area because of the possibility of volcanic eruption. Digit...

A characteristic of Australian stable continental region (SCR) faults appears to be the temporal clustering of large earthquakes. With the possible exception of active faults in the Flinders/Mt Lofty Ranges region of South Australia, active periods of earthquake activity comprising a finite number of large events are separated by much longer period...

Near-surface shear-wave velocity profiles were acquired at eighteen permanent and temporary seismograph sites in Western Australia, South Australia, Victoria and New South Wales. These data were obtained to support ground-motion modelling in Australia by characterising the near-surface response at sites used to record ground-motion from Australian...

Compared to the rest of continental Australia, the Flinders Ranges region of South Australia stands out not only because of its high topographic relief, but also because of its high seismicity and high fault density. The high density of thrust faults combined with their relatively high Quaternary slip rates indicate that the Flinders and Mt. Lofty...

Since September 2001, the small rural community of Burakin, southwest Western Australia, has been at the focus of seismic activity in Australia. In the six month period following commencement of seismicity, some 18,000 events had occurred, the largest of which having a moment magnitude of M 4.6. At the onset of activity, Geoscience Australia made a...

In Australia, the extreme infrequency of large earthquake events means that the historic record of seismicity is poorly suited to the task of assessing seismic hazard. Paleoseismological investigations provide the only viable avenue to obtain constraints on the recurrence intervals of large and damaging earthquakes. However, the prehistoric record...

We describe the use of a temporary seismometer deployment to monitor local earthquakes in the Flinders Ranges, South Australia. 16 seismograph stations were deployed over a 200 x 100 km area, which is one of the most seismically active regions in Australia. The instrumentation consisted of short-period and broadband Guralp seismometers combined wit...

Are there any earthquakes in Australia? Although most Australians are not as familiar with earthquakes as citizens in countries such as Japan, there are some quakes on the Australian continent every year. Differential Synthetic Aperture Radar Interferometry (DInSAR) has been widely used in recent years for monitoring crustal deformation due to eart...

The crust-mantle boundary is defined seismologically by the Mohorovicic discontinuity (or Mono), where the velocity of seismic waves increases from typical crustal values to typical mantle values. The depth of the Moho beneath Australia has been mapped using all available seismic data in order to study the crustal thickness patterns and their relat...

Australia has a low rate of modern seismicity and a short historical record of earthquakes. Both of these factors combined make it difficult to construct an earthquake hazard map for Australia in which we can have complete confidence. The current hazard map is based exclusively on historical and instrumentally recorded seismicity. It is an open que...

In March 1995, 44 land-based recorders were deployed throughout Tasmania, SE Australia, to record seismic energy from an encircling array of marine normal-incidence reflection shot lines. We invert refraction and wide-angle reflection traveltimes for crustal structure, with the principal outcome being a map of the Tasmanian Moho. Key tectonic infer...

We present a method for the determination of crustal structure by simultaneous inversion of seismic refraction and wide-angle reflection traveltimes for 3-D interface geometry and layer velocity. Crustal structure is represented by layers in which velocity varies linearly with depth, separated by smooth interfaces with a cubic B-spline parametrizat...

Wide-angle seismic data from ocean bottom seismographs, together with gravity and deep marine reflection profiling data along the Vulcan transect in northern Australia, define the crustal-scale features between the Precambrian Australian craton and the Timor Trough. The transect provides an outline of crustal and upper mantle architecture across th...

The island of Tasmania in southeast Australia consists of a number of stratotectonic elements. The relationships between these elements are largely obscured by younger cover of the Tasmania Basin, which contains extensive dolerite sills that limit the ability of potential field techniques to map basement. Therefore the development of a robust tecto...

High quality refraction and wide-angle reflection seismic data recorded by ocean-bottom seismographs (OBSs) deployed by the Australian Geological Survey Organisation along the 700 km long transect in the Carnarvon Basin effectively supplement results obtained by means of the conventional reflection technology. Velocity information can now be derive...

The attenuated continental crust between the Kimberley Block and the Timor Trough hosts some of the major oil and gas fields in Western Australia. The crustal structure has been interpreted from wide-angle seismic data acquired by the Australian Geological Survey Organisation during 1995/96. Ten ocean-bottom seismometers were deployed along a deep...

The Otway Basin in southeastern Australia formed on a triangular‐shaped area of extended continental lithosphere during two extensional episodes in Cretaceous to Miocene times. The extent of the offshore continental margin is highlighted by Seasat/Geosat satellite altimeter data. The crustal architecture and structural features across this southeas...

The ocean-bottom seismograph (OBS) data recorded in the Petrel sub-basin with a 100 m shot interval were not spatially aliased with respect to prevailing velocities and frequencies. This enabled the utilisation of digital seismic processing techniques not normally used to process refraction and wide-angle data. F-k filtering was used to enhance sig...

The Otway Basin in southeastern Australia formed on a triangular-shaped area of extended continental lithosphere during two extensional episodes in Cretaceous-to-Miocene times which ultimately led to the separation of Australia and Antarctica. The velocity structure and crustal architecture of the Otway continental margin has been interpreted from...

The Proterozoic Mount Isa Inlier in northern Australia is prospective for base metals and gold. It contains a Western Fold Belt (including the Leichhardt River Fault Trough) and an Eastern Fold Belt, separated by older basement rocks of the Kalkadoon Leichhardt Belt. Sediments and volcanics in both fold belts were deposited in rifts which were subs...

Wide-angle seismic profiling along the Otway Continental Margin Transect defines the velocity structure from the continental crust onshore to the deep Southern Ocean across an area of extended and faulted basement to the Otway Basin. A significant section of Otway Basin sequences (up to 5 km) lies offshore on the continental slope overlying uppermo...

Refraction/wide-angle seismic data recorded along the Mount Isa seismic transect show considerable lateral variation in velocity. Low-velocity layers are common in the crust and in the crust-mantle transition zone, and lateral variations in velocity are apparent in the upper 15 km of the crust. In the western Fold Belt, velocities are typically 5.7...

Wide‐angle reflection and refraction seismic studies indicate that two velocity models are appropriate for the structure of the crust and upper mantle under the New England Batholith, eastern Australia. Under the southern part of the batholith crustal velocities increase gradually from 5.5–6.03 km/s at the surface to 6.45 km/s near a distinct Moho...

The Redbank Thrust Zone in central Australia is a major Proterozoic Province boundary that was reactivated during the compressional Alice Springs Orogeny (300-400 Ma). To investi-gate its three-dimensional structure, three deep seismic reflection profiles were recorded over this boundary in 1985' This paper presents new seismic ¡esults that provide...

A regional 1650 km grid of deep seismic reflection data and complementary ship-shore refraction data is being used to study the deep structure of the Gippsland Basin. Preliminary results indicate that within the Cental Deep of the basin there appears to be little development of highly rotated fault blocks that are characteristic of most rift basins...

Seismic reflection sections for the Arunta Block generally show abundant, steep, north-dipping events that are interpreted as reflections from dipping faults, many of which are evident in surface geological mapping. The Redbank Thrust Zone, a major thrust feature, has been imaged to depths of at least 30 km. South of the Redbank Thrust Zone, steep,...

In 1988 and 1989, the Bureau of Mineral Resources (BMR) completed two regional seismic reflection surveys in the Gippsland and Bass Basins. Seismic arrivals from the routine air-gun shots fired during these surveys were recorded on land by BMR and the Department of Earth Sciences, Monash University. Individual analogue and digital recording station...

Deep Seismic profiling undertaken in central Australia comprised expanding spread reflection profiling, long-range refraction work and a small-scale three-dimensional refraction survey, as well as the more usual near-vertical incidence reflection profiling. Scismic reflection sections within the Arunta Block in central Australia show abundant north...

P-wave velocity models of the crust and upper mantle under the basins of southern Queensland, interpreted from seismic refraction/wide angle reflection profiles, indicate lateral inhomogeneities at many levels within the lithosphere. Velocity/depth models for basement below the central Eromanga Basin, the Nebine Ridge, the Taroom Tough of the Bowen...

Seismic refraction studies along a 262.5 km traverse in the Central Eromanga Basin have determined the detailed velocity structure of the basin, its infra-basins, and the upper crustal basement. Data were coincident with six-fold CMP reflection profiling and regional deep refraction profiling across the eastern Cooper Basin, Warrabin Trough, Canawa...

The Amadeus Basin in central Australia contains two commercial petroleum fields in a sedimentary succession up to 14 km thick that has been deformed by thrusting and large-scale folding during the Late Palaeozoic Alice Springs Orogeny. The 1985 BMR deep seismic profiling experiments were designed to test the various models that have been proposed f...

The crustal structure of the magnetic quiet zone outboard of the Otway Basin of the Australian southern margin is interpreted for the whole crustal section using fully processed multichannel seismic reflection data, seismic refraction data and dredge data collected by the Australian Bureau of Mineral Resources (BMR) vessel Rig Seismic, and extrapol...

Seismic refraction data were obtained for the Bass and Gippsland Basins during the 1988 cruise of the BMR research vessell "Rig Seismic". Seismic recorders were deployed on land by BMR and Monash University to record long-offset wide-angle reflection and refraction data using the ship's air-guns as the energy source. Preliminary results have now be...

Bas Hensen's mob

Bas Hensen's mob

To investigate the tectonic evolution of the Arunta Block and the Ngalia and Amadeus Basins, a regional north-south seismic reflection line 420km long from the Northern Arunta Province to the southern part of the Amadeus Basin, and an east-west refraction profile over 400km within the Arunta Block, were recorded by the Bureau of Mineral Resources i...

This report brings together most of the published velocity-depth information available for the deep crust and upper mantle of Australia, from surveys with data from below approx 5km depth. The velocities and depths for each model are listed, together with references, a plot of the velocity-depth curve, and location of the survey. The velocity model...

The Nebine Ridge in southeastern Queensland has crustal velocity features determined from wide‐angle reflection/refraction seismic data which contrast it with areas of thick sediment under the Eromanga Basin to the west. The depth to the crust/mantle boundary is at least 38 km; at this depth the interpreted P‐wave velocity of 7.7 km/s is low by com...

The major objective of the Central Australian seismic experiment is to investigate the structural evolution of the Arunta Block and the Ngalia and Amadeus Basins. A regional north-south reflection line of 420 km length from the Northern Arunta Province to the southern part of the Amadeus Basin was recorded in 1985. The most significant basement fea...

In 1985, the Bureau of Mineral Resources (BMR) recorded a regional deep seismic reflection profile of 420 km length from the Northern Arunta Province to the southern part of the Amadeus Basin (Fig. 1); record lengths were 24 s. An additional 90 km of reflection recording were obtained in the form of cross lines or parallel lines. Experimental refle...

Seismic refraction studies in Australia reveal a direct correlation between crustal thickness and average seismic velocity in the crust—thick crust has a higher average seismic velocity than thin crust. The velocities in the upper crust do not vary with crustal thickness. The increase in average crustal velocity is achieved wholly within the lower,...

Seismic refraction recordings along a line extending from Mt Howitt 1 to Eromanga, over Eromanga and Cooper Basin sediments, revealed 2 intra-basement refractors not recorded by co-incident reflection profiling. These refractors were recorded at 3.5 and 5.0 km depth between the basal unconformity at 2.4 km depth and a low velocity zone at about 8.5...

The crustal structure of the central Eromanga Basin in the northern part of the Australian Tasman Geosyncline, revealed by coincident seismic reflection and refraction shooting, contrasts with some neighbouring regions of the continent. The depth to the crust-mantle boundary (Moho) of 36–41 km is much less than that under the North Australian Crato...

Seismic refraction recordings along a line extending from Mt Howitt No. 1 well to Eromanga in southwest Queensland, over the Eromanga and Cooper basin sediments, revealed two intra-basement refractors not recorded by coincident reflection profiling. These refractors were recorded at 3.5 km and 5.0 km depth between the basin/basement unconformity at...

The Jurassic-Cretaceous Eromanga Basin in eastern Australia is a relatively undisturbed sedimentary sequence covering the Devonian Quilpie Trough and the Early Palaeozoic Canaway Ridge and Cheepie Shelf. Seismic refraction recording across these three features, with additional reflection, gravity, and well information, has been used to determine th...

Deep seismic refraction and vertical reflection recordings have been made in the southern McArthur Basin, over the Bauhinia Shelf and Batten Trough between Daly Waters and the H.Y.C. mineral deposit, and over the Wearvan Shelf between Borroloola and Westmoreland. In the Batten Trough, McArthur Group rocks have a velocity of 5.81 km/s; no velocity c...

Current methods of interpreting seismic data from earth-quake or explosion sources in terms of geological structures use both the kinematic and dynamic information in the data. This requires that the characteristics of the systems used for recording and analysing ground motion be well known, and in recent years this requirement has been allied with...

Seismic investigations of the Earth's crust in the Lachlan Fold Belt of southeastern Australia, under the continent's highest mountain ranges, indicate a depth to the Moho of between 40 and 52 km, with P-wave velocities in the upper crust of 5.6–6.3 km s−1, lower crustal velocities of 6.7–7.4 km s−1, and upper mantle velocities of 8.0–8.1 km s−1. V...

The interpreted velocity-depth structure in the crust of the lachlan Fold Belt in southeastern Australia indicates that velocity gradients, rather than discontinuous velocity changes, characterise region. The velocity-depth morphology varies across the region. In the upper crust at depths less than 12km, there is evidence in three areas for velocit...

Interpretation of seismic refraction data from the SW coast of the Papuan Peninsula and the NW Coral Sea gives consistent results using several inversion techniques. Sediments over the Papuan Plateau are 5 km thick; to the W and NW they thicken to 10 km along the axes of the Moresby and S Aure Troughs. Farther out into the Coral Sea, over the E Pla...

Geophysical interpretation of crustal structures in the region of the Papuan Ultramafic Belt shows that the belt consists of a major dipping layered structure with velocities similar to those found in Alpine ophiolite sequences. However, the thickness of crustal material seaward of the belt is probably too great to be oceanic in origin, a feature i...