NOAA CENTER FOR TSUNAMI RESEARCH
Stuart Weinstein Scott, we had a good location from the getgo. Most intraplate quakes are dip-slip events,
and the controlling factor as to whether they are thrust or normal is lithiospheric age. Doug Wiens presented
that work in his PH.D. thesis. Intra-plate strike slip events are rare. These two Sumatra quakes are the
largest instrumentally recorded intra-plate quakes. they are also the largest instrumentally recorded
strike-slip quakes, at least as far as I know.
YouTube video of an animation using the correct type and number of earthquakes
By Dailin Wang and Nathan Becker (Pacific Tsunami Warning Center)
Giant Avalanches and Mega-tsunami (not)
N coast of E. Moloka‘i
WHAT CAUSED THE HUGE PALI? FAULTING? MARINE EROSION?
VALLEY EROSION? SOME COMBINATION OF THESE?
Dana (1890) “Thus such precipices are rather the rule in the Hawaiian group; and if seashore
erosion is not the origin, - as many facts from the islands of the Pacific appear to show, fractures and subsidence must be.
Formation of a cliff (that might be, or has been, mistaken for a
fault or avalanche scarp) by coalescence of amphitheater-headed
valleys
(Modified from Stearns & Vaksvik 1935)
“Topographic evidence indicates the
presence of two large submarine
landslides on the slope of the Hawaiian
ridge northeast of Oahu. One slide is
more than 150 km long and moved on a
slope with an overall gradient of about
2 degrees.” (Moore 1964)
“However, recent detailed work on the topography of the region…does not support this
hypothesis. The undersea hills are very large
as compared with the bumps on known landslides, and some of them have forms characteristic of volcanic cones. The Tuscaloosa
(also called Tuscarora) Seamount, for example,
has a height of about 6,000 feet above the
surrounding sea floor, and its general form…
suggests that it is probably a guyot…”
(Macdonald and Abbot 1970)
(Moore 1964)
GLORIA side-scan
sonar data (smooth
surfaces show up as dark,
rough surfaces show up
as bright)
(Moore et al. 1989)
(Moore et al.
1989)
actual
avalanche
scarps
obvious cliffs
after Moore (1964)
Nu‘uanu
Debris
Avalanche
Ka‘ena
Slump
Wailau Slide
Wai‘anae
Slump
(slide by John Sinton)
Profiles through E. O‘ahu showing landslide blocks (~3x vertical exaggeration)
Landslide headwall
E. O‘ahu - restored
Wai‘anae
Diagrams by Moore and Clague [2002], slide by John Sinton
potential giant avalanche
slide-plane?
17 large landslides in principal
Hawai‘i region
Represents ~6 million yrs (= 1 every
350,000 yrs)
Two Kinds: slumps (prolonged,
progressive formation) and
catastrophic debris avalanches
Off-shore failure accelerates onshore erosion
Debris avalanches are likely to
produce huge tsunami locally, but
Would they be Pacific-wide?
(Lamb et al. 2007)
A deposit of coral and basalt boulders resting ~conformably
on basalt flows, ~100 m above sea level, S. coast of Lana‘i
Moore and Moore (1988):
the Hulopoe Gravel was
deposited by giant waves
(megatsunami) generated
by large submarine
landslides.
Moore and Moore (1988) also
speculated that other high-level
deposits elsewhere in Hawai‘i
might also be explained with this
mechanism
(slide by John Sinton)
Rubin et al. (2000) dated
carbonates from the deposit:
-Age correlates with stratigraphic
height
-None of the clasts indicate a 105
ka “event”
(slide by John Sinton)
The deposit is too old to
have been produced from
the Alika Slide (a ~105,000
year-old avalanche
deposit on the W. flank of
Mauna Loa)
The presence of internal
stratigraphy indicates it is
not the product of a singe
event (or wave)
Rubin et al. [2000]
(slide by John Sinton)
These results favor
deposition from rising
and falling sea level over
a period of more than
100,000 years (scenario
B).
The boulders are sorted
by age:
Different sea levels?
Multiple tsunami?
~1 m
Felton et al. [2000] recognized up to 14
different beds in the unit, and 8 different
disconformities in the 9-m thick type
section.
Three of the disconformities are associated
with truncated paleosols
The deposition of the Hulopoe Gravel was
not continuous.
At least one bed is clearly alluvial
(slide by John Sinton)
Photo by Peter Mouginis-Mark, HIGP/SOEST
A Wave of Destruction Will
Destroy America's East Coast
By Ian Gurney
The Daily Express - UK
8-10-4
http://www.toptenz.net/top-10-craziest-ends-to-civilizations-as-we-know-it.php/megatsunami
Ward SN (2001) Landslide Tsunami. J Geophys Res 106:
11201-11215
Ward SN (2001) Landslide Tsunami. J Geophys Res 106:
11201-11215
Ward SN (2001) Landslide Tsunami. J Geophys Res 106:
11201-11215
Ward SN (2001) Landslide Tsunami. J Geophys Res 106:
11201-11215
Ward SN, Day S (2001) Cumbre Vieja Volcano – Potential collapse and tsunami at La Palma, Canary
Islands. Geophys Res Lett 28:3397-3400
Ward & Day (2001)
http://geology.com/news/images/canary-islands-la-palma.jpg
http://www.eosnap.com/public/media/2009/01/canaryislands/20090121-canaryislands-full.jpg
http://www.geo.arizona.edu/%7Eandyf/LaPalma/1949-Faults.jpg
http://geology.com/news/2005/09/atlantic-ocean-tsunami-threat.html
http://www.lapalma-tsunami.com/reactions.html
A web version of this is at
http://www.drgeorgepc.com/TsunamiMegaEvaluation.html
http://www.tsunamisociety.org/PressReleases.html