ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

Electronic Resource

Island Edifice Failures and Associated Tsunami Hazards (2000)

Keating, B. H. ; McGuire, W. J.

Springer

Pure and applied geophysics 157 (2000), S. 899-955

add to mindlist on the mindlist

Details

ISSN: 1420-9136

Keywords: Key Words: Island, edifice failure, landslide, tsunami.

Source: Springer Online Journal Archives 1860-2000

Topics: Geosciences , Physics

Notes: Abstract —Volcanic ocean islands are prone to structural failure of the edifice that result in landslides that can generate destructive tsunamis. These island landslides range enormously in size, varying from small rock falls to giant sector failures involving tens of cubic kilometers of debris. A survey of literature has allowed us to identify twenty-three processes that contribute to edifice collapse. These have been divided into endogenetic and exogenetic sources of edifice failure. Endogenetic sources of instability and failure include unstable foundations, volcanic intrusions, thermal alteration, edifice pore pressures, unbuttressed structures, and buried faults. Exogenetic sources of instability and failure include collapse of subaerial or submarine deposits, endo-upwelling, karst megaporosity, fractures, oversteepening, overloading, sea-level change, marine erosion, weathering including hurricanes, glacial response, volcanic activity, regional uplift or subsidence, tectonic seismicity and anthropogenic agents. While the endogenetic sources dominate during periods of active volcanism and cone building, the exogenetic sources may cause failure at any time. Tsunamis, both small and large, are associated with these edifice failures.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s000240050011

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Sonar Studies of Submarine Mass Wasting and Volcanic structures off Savaii Island, Samoa (2000)

Keating, B. H. ; Helsley, C. E. ; Karogodina, I.

Springer

Pure and applied geophysics 157 (2000), S. 1285-1313

add to mindlist on the mindlist

Details

ISSN: 1420-9136

Keywords: Key Words: Landslides, submarine volcanism, Pacific, Samoa.

Source: Springer Online Journal Archives 1860-2000

Topics: Geosciences , Physics

Notes: Abstract —Sidescan sonar observations show that mass wasting plays an important role in the geologic development of the Savaii Island edifice. Observations on the south and west flanks indicate that debris movement on the submarine slopes between rift zones is characterized by large sheets of unchannelized debris. Farther downslope these sheets have slumped into folded although still relatively coherent slump sheets. Closer to the rift zones, more chaotic slumps are found. The presence of large detached landslide blocks, without obvious upslope headwall scarps, suggests that earlier slumps are covered by subsequent veneers of debris moving downslope.¶In contrast, on Stearns Bank west of the island of Savaii most of the features are of constructional origin, formed during the building of this volcanic edifice of unknown age. Two prominentsubmarine platforms are evident, the shallower one with a summit cone. Sea cliffs and subdued terraces record platforms cut by sea-level oscillations late in the history of the volcanic edifice. Fractures and fissures are present on the bank, however there is little evidence of landslides in this area. The absence of landslides may reflect differing ages of the bank and the island or the edifice could have remained submarine during its construction with few or no subaerially derived ashes and clays present to facilitate mass wasting.¶We conclude that mass wasting is an important influence on the evolution of the Savaii volcanic edifice. It appears that sediment and debris cover most of the slope outside the submarine rift zones. The sonar images indicate that mass wasting is a common process in the submarine environment. Unlike the giant landslides documented by GLORIA imagery around the Hawaiian Islands, the southern margin of Samoa is characterized by numerous small slumps and slides. Although we have little information at present regarding the recurrence interval for submarine landslides, their ubiquitous presence in these sidescan sonar records indicates that they are an important component of the geologic record of the Samoan Islands.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s000240050026

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

The Hulopoe Gravel, Lanai, Hawaii: New Sedimentological Data and their Bearing on the “Giant Wave” (Mega-Tsunami) Emplacement Hypothesis (2000)

Felton, E. A. ; Crook, K. A. W. ; Keating, B. H.

Springer

Pure and applied geophysics 157 (2000), S. 1257-1284

add to mindlist on the mindlist

Details

ISSN: 1420-9136

Keywords: Key Words: Gravel, facies analysis, coastal sedimentation, rocky shoreline, ocean island, Hawaii, tsunami, submarine landslide.

Source: Springer Online Journal Archives 1860-2000

Topics: Geosciences , Physics

Notes: Abstract —Recognition that many oceanic islands are shaped by giant landslides has highlighted claims that the Hulopoe Gravel on south Lanai, Hawaii, was deposited by giant waves (mega-tsunami) generated by such a landslide. This interpretation is controversial. Resolution of the controversy has global implications because mass wasting of oceanic islands has been a common process for as long as hot spot volcanism has affected the ocean basins. Thus, if mega-tsunami are attendant upon the mass wasting process, their effect on earth surface processes should be discernible for much of geological time and may be comparable to that resulting from bolide impacts that form astroblemes.¶Detailed facies analysis of the pebble, cobble and boulder gravels that form the Hulopoe Gravel type section shows that the gravels are composed predominantly of basalt clasts with appreciable amounts of limestone clasts in 8 of the 14 beds present. Deposition was not continuous: eight disconformities are recognized in the 9.2 m type section, three of which are associated with truncated paleosols. The Hulopoe Gravel was not deposited by a single tsunami at 105 ka, as has been proposed. One bed is clearly an alluvial deposit. The origins of others are unclear but the facies data do not exclude tsunami as one of the processes that deposited individual beds within the Hulopoe Gravel, either above or below sea level.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s000240050025

Permalink