Submarine landslides on the Great Barrier Reef shelf edge and upper slope: A mechanism for generating tsunamis on the north-east Australian coast?

TY - JOUR

T1 - Submarine landslides on the Great Barrier Reef shelf edge and upper slope

T2 - A mechanism for generating tsunamis on the north-east Australian coast?

AU - Webster, Jody M.

AU - George, Nicholas P J

AU - Beaman, Robin J.

AU - Hill, Jon

AU - Puga-Bernabéu, Ángel

AU - Hinestrosa, Gustavo

AU - Abbey, Elizabeth A.

AU - Daniell, James J.

PY - 2016/1/1

Y1 - 2016/1/1

N2 - Shallow (<200 m) submarine landslides influence margin evolution and can produce devastating tsunamis, yet little is known about these processes on mixed siliciclastic-carbonate margins. We have discovered seven landslides along the shelf edge and upper slope of the central Great Barrier Reef (GBR), Australia. The largest shelf edge landslide is investigated in detail and represents a collapse of a 7 km long section of the shelf edge at 90 m water depth with coarse debris deposited up to 5.5 km away on the upper slope down to 250 m. The precise timing and triggering mechanisms are uncertain but available chronologic and seismic stratigraphic evidence suggests that this event occurred during the last deglacial sea-level rise between 20 and 14 ka. Regional bathymetric data confirms that these shelf edge and upper slope slides are restricted to the central GBR between latitude 18° and 19°S, suggesting a spatial relationship between the extensive Burdekin paleo-fluvial/delta system and shallow landslide activity. This study highlights an important local mechanism for the generation of tsunamis on this margin type, and numerical simulations under present conditions confirm that a 2 to 3 m tsunami wave could be produced locally. However, we consider that the risk of such slides, and their resulting tsunamis, to the modern coastline is negligible due to their relatively small size and the capacity of the GBR to dissipate the wave energy.

AB - Shallow (<200 m) submarine landslides influence margin evolution and can produce devastating tsunamis, yet little is known about these processes on mixed siliciclastic-carbonate margins. We have discovered seven landslides along the shelf edge and upper slope of the central Great Barrier Reef (GBR), Australia. The largest shelf edge landslide is investigated in detail and represents a collapse of a 7 km long section of the shelf edge at 90 m water depth with coarse debris deposited up to 5.5 km away on the upper slope down to 250 m. The precise timing and triggering mechanisms are uncertain but available chronologic and seismic stratigraphic evidence suggests that this event occurred during the last deglacial sea-level rise between 20 and 14 ka. Regional bathymetric data confirms that these shelf edge and upper slope slides are restricted to the central GBR between latitude 18° and 19°S, suggesting a spatial relationship between the extensive Burdekin paleo-fluvial/delta system and shallow landslide activity. This study highlights an important local mechanism for the generation of tsunamis on this margin type, and numerical simulations under present conditions confirm that a 2 to 3 m tsunami wave could be produced locally. However, we consider that the risk of such slides, and their resulting tsunamis, to the modern coastline is negligible due to their relatively small size and the capacity of the GBR to dissipate the wave energy.

KW - Continental shelf

KW - Great Barrier Reef

KW - Numerical model

KW - Sea-level change

KW - Submarine landslides

KW - Tsunami

UR - http://www.scopus.com/inward/record.url?scp=84948140528&partnerID=8YFLogxK

U2 - 10.1016/j.margeo.2015.11.008

DO - 10.1016/j.margeo.2015.11.008

M3 - Article

AN - SCOPUS:84948140528

SN - 0025-3227

VL - 371

SP - 120

EP - 129

JO - Marine Geology

JF - Marine Geology

ER -