In April 2015 Geoscience Australia (GA) acquired 908 km (full-fold) Gippsland Southern Margin Infill 2D Seismic data using Gardline's M/V Duke. The survey is designed to better resolve the Foster Fault System and provide better integration between the GDPI10 survey and the existing surveys in the central deep. The data underwent pre-stack depth migration with a deghosting algorithm during processing. The dataset includes intermediate processing products as well as final preSTM and preSDM and associated velocities.

Several belts of poorly-exposed igneous rocks occur in the Grampians-Stavely Zone of western Victoria, close to the interpreted Cambrian east Gondwana continental margin. Previous geochemical studies on the outcropping igneous rocks around Mount Stavely, Mount Dryden and in the Black Range have recognised characteristics similar to those found in modern magmatic arcs. These rocks are collectively considered to form part of a single Middle to Late Cambrian arc system, referred to as the Stavely Arc. While outcropping examples of the Stavely Arc magmas are well studied, the character of other (likely) arc-related rocks imaged by magnetic data beneath recent, thin cover has remained enigmatic. New geochemical data from a recent stratigraphic drilling program, together with analysis of rocks from government and industry drill holes has allowed for a more complete understanding of the Stavely Arc package. A range of rock associations have been recognised, including low-Ti boninite-like rocks, back-arc-related tholeiitic rocks, adakitic porphyry intrusives, serpentinites, and highly-depleted mafic to intermediate volcanics and intrusives. The majority of arc-related rocks comprise low- to high-K calc-alkaline basalt, andesite, dacite, and geochemically-related quartz diorite, which display similar N-MORB-normalised trace element patterns, LREE-enriched REE patterns and moderately evolved to weakly juvenile Nd isotopic compositions (Nd 500 Ma = -3.95 to +0.46). High-Al basalts intersected during stratigraphic drilling also show weakly-developed calc-alkaline compositions. However, these are distinguished from the other calc-alkaline rocks by higher Al2O3, N-MORB-like trace element patterns, relatively flat REE patterns and much more juvenile Nd isotopic compositions (Nd 500 Ma = +4.73 to +6.33). High-Al basalts are spatially associated with boninites intersected by mineral exploration drilling. The earliest geochronological evidence for Stavely Arc magmatism is provided by an isotopically juvenile felsic intrusive with an interpreted arc-related origin dated at ~510 Ma. This age is synchronous with tholeiitic dolerite from the western Grampians-Stavely Zone interpreted to have been emplaced in a back-arc extensional setting. Available ages for volcanic rocks of the Stavely Arc are only known from the Mount Stavely Belt, and show that arc magmatism reached maturity around ~505-500 Ma. Overall geochemical systematics suggest that the majority of calc-alkaline rocks of the Stavely Arc have affinities with modern island arcs with (limited) continental crust involvement. It is unlikely that the thickness of any pre-existing Precambrian crust was great, given the Nd isotopic compositions and lack of inherited Mesoproterozoic or older zircons. In comparison, the more juvenile isotopic characteristics, weakly-developed subduction-related features, and spatial association with boninites of the high-Al basalts are more consistent with a more primitive arc setting, and may represent an (early?) phase of Stavely Arc magmatism in which there was insignificant crustal involvement. Similar geochemical characteristics, ages, and inferred tectonic setting are consistent with the Stavely Arc forming part of a larger Middle to Late Cambrian arc system that also includes the Mount Wright Arc in New South Wales and the Jamison Volcanic Group (Selwyn Block) in central Victoria.

The largest southeastern Australian earthquake this century occurred in the West Tasman Sea, 100 km east of Flinders Island, at 1948 UTC on 14 September 1946. Its epicentre was at 39.97°S, 149.35°E and its Richter magnitude ML 6.0. It was felt strongly throughout Tasmania and Gippsland, Victoria, and caused minor damage in Launceston. The isoseismal map of the earthquake is consistent with lower strong ground motion attenuation in Tasmania than in mainland southeastern Australia, and the macroseismic effects suggest amplification of seismic shaking by Tertiary lake sediments in Hobart and Launceston.

Sandy clays deposited during the waning phase of Oligocene-Middle Miocene transgression of the Murray Basin conformablyoverlie the shallow to marginal marine Geera Clay and grade laterally into fluvio-Iacustrine sediments of the Middle and Upper Renmark Group. These sandy clays (informally named "Geera Clay equivalent") and the Geera Clay preserve marine dinoflagellates that became extinct by middle to late Middle Miocene time. If the subsequent regression was due to a global drop in relative sealevel, then we propose that the unconformity developed across the Geera Clay and that the lateral equivalents during the Late Miocene (Mologa weathering surface) correlates with either the 13.8 Ma or (preferred) 10.5 Ma sequence boundary of Haq and others (1987). Three pollen species of potential biostratigraphic value in the Murray Basin are illustrated and discussed. One new species is described: Tetrapollis campbellbrownii.

A new function for -logAo has been deduced, and parameters determined using nonlinear regression analysis of data from the Victorian seismograph network. The formula for local magnitude supplied within the article has been adopted for the Victoria region. The values of - logAo closely follow the trend of Richters values at medium hypocentral distances. The features of Bakun and Joyners (1984) formula at close range, which were found to be applicable in Victoria, have been retained. The formula is applicable for distances from a few kilometers, and the maximum distance has been extended from 600 to 1000 km. The value of logS is closely related to the seismometer foundation, varying from about 0.0 at a bedrock site to more than 0.7 at soft sedimentary sites. The determination and application of site corrections is examined in detail.

Dinoflagellates offer a reliable method for distinguishing the Late Miocene-Early Pliocene Bookpurnong beds from lithologically similar marginal marine sediments, such as the Winnambool Formation deposited during Oligocene-Middle Miocene transgressions. Species largely or wholly restricted to the Bookpurnong beds and correlatives in the central west Murray Basin include Melitasphaeridium aequabile, M . choanophorum, Tectatodinium psilatum , and (frequent) Tuberculodinium vancampoae. Species diagnostic of the older Murray Group correlatives, such as the Geera Clay and Winnambool Formation, include Apteodinium australiense and Pentadinium laticinctum.

Fossil spores and pollen preserved in the Late Miocene-Early Pliocene Bookpurnong beds and correlatives of the central west Murray Basin allow a new palynological zone to be recognized: the Monotocidites galeatus Zone. In vertical succession, the zone overlies the late Early-Late Miocene Triporopollenites bellus Zone and underlies as yet unzoned Late Pliocene-Pleistocene palynosequences. Species described as new herein include: Densoisporites implexus, D. simplex, Rhoipites ampereaformis, R. cissus, R. muehlenbeckiaformis, R. risus, Myrtaceidites lipsis, Proteacidites punctiporus, Malvacipollis regattaensis, Monotocidites galeatus, and Acaciapollenites weissii.

The Early Cretaceous non-marine volcaniclastic Eumeralla Formation accumulated in a rift basin on the southern margin of Australia during the break-up of eastern Gondwana. Wireline-Iog analysis and a range of sedimentary data have helped to discriminate three major basin-wide informal lithostratigraphic units in the formation. From the base of the formation they are: Eumeralla I: siltstone/mudstone/sandstone/coal; Eumeralla II: siltstone/mudstone/thin lithic sandstone; and Eumeralia III: volcaniclastic sandstone. A fourth unit - Eumeralla IV: siltstone/sandstone/coal - occurs throughout the western Otway Basin, but is absent, probably because of erosion, from the central and eastern pans of the basin. The bases of all four lithostratigraphic units are probably diachronous. The succession of lithostratigraphic units Eumeralla I- IV is interpreted as representing coal swamps and flood plains of low-energy streams; shallow and deep freshwater lakes; channel tracts and flood plains of high-energy streams; and channel tracts, flood plains and coal swamps of low- energy streams respectively. Sedimentary facies analysis of outcropping Eumeralla II and Eumeralla III in the eastern Otway Basin confirms the interpretations for these units. The basin-wide extent of the three lower lithostratigraphic units implies that a single integrated drainage system for the entire basin was established at the onset of Eumeralla Formation deposition, and persisted at least until the late Albian. This inference is supported by the close correlation between variations in lithology and depositional environments and the Aptian- Albian sea-level changes. However, intrabasinal volcanism significantly influenced sedimentation and was probably the primary control on basin drainage.

A new expression with superior consistency in the calculation of magnitude from earthquake coda duration has been developed. The need to take into consideration the site, the seismograph characteristics and the source has been investigated. The expression is valid for distances up to 1000 km in southeast Australia except where the source is located on some other major geological foundation, for example the Australian shield or the Tasman Sea. The expression takes the form: MD = p1 + p2(log(SDD))P3 + p4Re-p5R . MD is duration magnitude, and the parameters in the above expression are determined by regression based on local magnitude ML. Duration, D, is in seconds, R is the hypocentral distance in kilometres, and pn are parameters. Parameter p1 zeroes the function to give values similar to ML and accounts for the definition of duration; p2 and p3 give the shape of the variation with duration; and p4 and p5 give the variation with distance. SD is the duration site correction factor , which varies from site to site and can be easily determined by comparing particular site durations with average durations. If the network data are electronically recorded, the value of SD for all sites can be continually monitored and updated. Because of the different methods of estimating D for the analogue and digital seismographs, a value of the parameter p1 for each seismograph type is necessary. analogue MD = - 0.46 + 0.45(log(SDD))2.4 + 0.0045Re-0.002R . digital MD = - 0.20 + 0.45(log(SDD))2.4 + 0.0045Re-0.002R . The above expressions present the relationship between MD, D (measured to double the background level) and R in southeast Australia for magnitudes between MD 0 and 5 and for distances from a few km to 1000 km.

The effective quality factor Q for S wave attenuation in the Victorian lithosphere has been calculated using both the spectral ratio and coda Q methods. The frequency range studied was 2-20 Hz, and Q was found to be frequency dependent. A simple model has been adopted, with a low Q in the top 4 km of the crust that varies from 20 at a frequency of 1 Hz to 60 at 10 Hz. The lower crust has a higher Q that varies from 100 at 1 Hz to 700 at 10 Hz. Empirical formulae for Q determined by linear regression of logarithmic plots of amplitude versus frequency are Q = 20f 0.5 for the 4 km thick upper crust, and Q = 100f 0.85 for the lower crust, where f is frequency.