Figure 6 - uploaded by Vic Dent
Content may be subject to copyright.
Source publication
This report is the 4th in a series of annual reports describing the annual seismicity of the South West Australia (SWA) zone since June 2013. In previous reports, 36 earthquake cluster localities were identified. In this report, covering the period June 2016-May 2017, 101 of the 207 events located by Geoscience Australia in the SWA zone have been r...
Contexts in source publication
Context 1
... zone was previously called "Meckering" but is now renamed "Kellerberrin" since the Meckering region has been excised to form the new zone "M". There are two pre-defined cluster locations in this zone (E1 and E2, Figure 6), but the only grouping of significance in the 2016-17 year is one of three events north of Doodlakine (August 2016 and April 2017). Relocations tighten the group, and the location appears to coincide with a cluster in June 1994 (grey events in Figure 6), which was noted in Dent (2008). ...
Context 2
... are two pre-defined cluster locations in this zone (E1 and E2, Figure 6), but the only grouping of significance in the 2016-17 year is one of three events north of Doodlakine (August 2016 and April 2017). Relocations tighten the group, and the location appears to coincide with a cluster in June 1994 (grey events in Figure 6), which was noted in Dent (2008). This is cluster location has not been named before, and is here defined as location E3. ...
Similar publications
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...
Citations
... Location map. Earthquake Zones of Dent (2014;2017). Earthquakes from July 2022 to June 2023 inclusive. ...
... four such regions in Australia for which he discussed the seismicity. Leonard's South West Australia region was divided by Dent (2014) into 8 latitudinally-based sub-zones, and later revised (Dent 2017) to the 10-zone configuration shown in Figure 1. The seismicity of SWA between July 2012 and June 2022 has been analysed from a "clustered" viewpoint in 8 previous reports by Dent and co-workers (eg. ...
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 magnitude 5.0 event near Gnowangerup. Most of the seismicity in this period occurs in 21 clusters; 10 were previously active and 11 are new. Of interest is the contemporaneous seismicity of 5 neighbouring cluster pairs, suggesting a possible causative link.
... It did not receive much more attention until Dent (2012) started listing and naming cluster centres. Fifty-one such centres have been defined so far (Dent 2017, and they are plotted on Figure 1. Some of the more significant clusters (i.e. containing at least one ML 4 event) are listed in Table 1 and are also shown (as black filled hexagons) in Figure 1. ...
... This was divided by Dent (2016) into eight zones by latitude, A-H (see Figure 1). Two of these zones were subdivided in Dent (2017), creating new zones L and M. In this paper, a new zone, (zone I), is appended to the east of the region to accommodate seismicity north of Ravensthorpe, and some other events which occurred during this study period. Also, zone A is extended northwards to include seismicity near Latham (Figure 1). ...
Earthquake clustering has long been noted as a significant feature of the seismicity of southwest Western Australia. The cluster locations are of significance because they are sites of repeating seismicity for over a decade or more. Fifty-one cluster centres have been previously defined, mostly from seismicity during the 2012-2017 period. Seismicity during 2017-2020 is reviewed here, resulting in the identification of 28 cluster centres active during this period. Of these, 14 had been active prior to 2017 and 14 are new. The most significant of these were northwest of Beacon, representing ongoing activity, and north of Ravensthorpe, which is a new location. The cluster centres in southwest Western Australia appear to define a NNW trend, as has been noted in earlier studies, and may correlate with the granitoid components of the geology in that region of the Yilgarn craton. The northern region of the study area has more cluster locations than the southern region, which is consistent with earlier studies of the seismicity of the region.
... Cluster location G5 was named inDent (2017) on the basis of an ML 2.4 event in April 2014, and about 20 small events (max ~ ML 1.5) recorded by the seismograph GNOC in August 2016. It is about 10 km west of the 2019 activity, and its estimated uncertainty is about +/-5 km. ...
Much of the seismicity in southwest WA occurs in localised groups of recurring earthquakes, or clusters. Four potential cluster sites have been identified in the Great Southern Region of WA in the period January to November 2019. A group near Newdegate contained the largest event of the year (ML 4.3), and it is suggested these events belong to an earthquake group first identified in 2016. The three other groups identified are near Denmark, Gnowangerup and Ongerup. Relocations of many of the events using the VIC5A earth model suggests tighter groupings for the events than the published Geoscience Australia locations. The Gnowangerup and Ongerup groups are also close spatially, and there may be a causal link between the groups. The region has been categorised as a region of relatively low seismicity, and the higher numbers of events in 2019 may be related to the occurrence of two ML 5 event in Lake Muir in late 2018. .
... These papers attempt to identify and provide some detail about the frequent earthquake clusters that occur in the region. Approximately 15 -20 clusters have been identified in each year, and a total of 44 cluster locations have been defined in previous reports by Dent (2014aDent ( , 2015Dent ( , 2016Dent ( & 2017. These cluster locations are shown in Figure 1. ...
... were recorded, correlating with an epicentral distance of about 21 km (Figure 6), assuming a shallow focal depth. Using these derived epicentral distances, the intersection of the circles ( Figure 6) suggests a common epicentre at 30.64 o S, 117.43 o E, which is about 3 km WNW of the location assigned to the events which occurred in 2013-2014(location F in Dent (2014a, or C1 in Dent (2017). This may represent a better location for the C1 cluster. ...
... The next largest was ML 2.4 northwest of Gnowangerup, on 19 April 2013. This event also appears isolated, but, as noted in Dent (2017), its location correlates with a cluster of small events in 2016 (none located by GA). It also correlates with a cluster of three events in November 2017 (largest ML 2.4), and is close to GA's location of an ML 3.7 event in October 1996 (-33.9, 117.909). ...
Clustered intra plate seismicity in south west Australia
