Legacy product - no abstract available

The Mount Lofty and Flinders Ranges of South Australia are bound on the east and the west by reverse faults that thrust Proterozoic and/or Cambrian basement rocks over Quaternary sediment. These faults range from a few tens to almost one hundred kilometres in length and tend to be spaced significantly less than a fault length apart. In the few instances where the thickness of overthrust sediment can be estimated, total neotectonic throws are in the order of 100-200 m. Slip rates on individual faults range from 0.02-0.17 mm/a, with one unconfirmed estimate as high as 0.7 mm/a. Taking into account the intermittent nature of faulting in Australia, it has been suggested that 30-50% of the present-day elevation of the Flinders and Mount Lofty Ranges relative to adjacent piedmonts has developed in the last 5 Ma. Uplifted last interglacial shorelines (ca. 120 ka) along the southern coastline of the Mount Lofty Ranges indicate that deformation is ongoing. Palaeoseismological investigations provide important insight into the characteristics of the large earthquakes responsible for deformation events. Single event displacements of 1.8 m have been measured on the Williamstown-Meadows Fault and the Alma Fault, with the former relating to a surface rupture length of a least 25 km. Further to the south in Adelaide's eastern suburbs, a 5 km section of scarp, potentially relating to a single event slip on the Eden-Burnside Fault, is preserved in ca. 120 ka sediments. Where the Eden-Burnside Fault meets the coast at Port Stanvac 20 kilometres south, the last interglacial shoreline is uplifted by 2 m relative to its expected position. At Normanville, on the uplifted side of the Willunga Fault, the last interglacial shoreline is over 10 m above its expected position, implying perhaps five or more surface rupturing events in the last ca. 120 ka on this >50 km long fault. On the eastern range front, a very large single event displacement of 7 m is inferred on the 54 km long Milendella Fault, and the 79 km long Encounter Fault displaces last interglacial shorelines by up to 11 m. There is abundant evidence for large surface-breaking earthquakes on many faults within 100 km of the Adelaide CBD. Slip rates are low by plate margin standards, implying a low rate of recurrence for M7+ events on individual faults (perhaps 10,000 years or more). However, a proximal moderate-sized event or even a large event at distance has the potential to cause significant damage to Adelaide, particularly given its construction types and local site conditions.

22-1/H52-08/8 Vertical scale: 100

H53/B1-76

22-1/H54-6/4 Vertical scale: 200

No abstract available

60% coverage south 22-1/G52-16/5 Vertical scale: 100

I53/B1-47 Vertical scale: 20

Legacy product - no abstract available

22-2/H53-2/2-6 Contour interval: 25