Abbreviated version of seminar provided to Scripps Insitution of Oceanography by Byron Washom on 4-6/11 on the impacts of the 3-11-11 Honshu Tsunami on Midway Atoll.

1. Midway Atoll Natural Wildlife Refuge
Papahānaumokuākea
Marine National Monument
Impacts of Honshu Tsunami
March 10-11, 2011
Byron Washom, UC San Diego
Presented at
Scripps Institution of Oceanography
April 6, 2011

8. The oldest known free-flying bird in US, ~ 60, an
albatross named “Wisdom”, hatches her chick
• Advanced age may be double or triple the
expected life span for a Laysan albatross,
• Oldest wild specimen documented during the 90-
year history of the U.S. and Canadian bird-
banding research program.
• She was first tagged with an identification band
at ~5 in 1956 while incubating an egg.
• She has logged about 3 million flying miles (4.8
million mile (~six round trips to the Moon).

9. March 10-11, 2011 Honshu Tsunami
• http://freevideocoding.com/flvplayer.swf?file
=http://flash.vx.roo.com/streamingVX/63056/
1458/20110311_japan_wave_successions_sky
_1000k.mp4&autostart=true

10. NOAA Animation
• http://www.youtube.com/watch?v=z9pXHlOtRTY

12. Bathymetry of Midway Atoll

15. History of Ocean Crossing Tsunamis
• Few observations, despite the five great ocean-crossing
tsunamis of the 20th century.
• The believed highest value was at Midway in 1952, when
runup reached 1.9 meters from the magnitude 9 Kamchatka
earthquake, and Midway was square in the center of the
radiated beam and only 3000 km from the source.
• Johnston Atoll, another atoll extensively modified by dredging,
where the Chile tsunami of 1960 had a runup of 0.7 meters.
• Of atolls not extensively modified to handle shipping, the
highest runup believed is Kiritimati in 1960, which recorded a
runup of 0.3 meters.
Source: Gerard Fryer at the NOAA Pacific
Tsunami Warning Center

16. Why should the hazard be so low?
• The sea level has risen since the last glaciation, and for the last
18,000 years, coral has been growing almost vertically upwards.
• As a consequence, each atoll in the Pacific has very steep upper
slopes, making the island look pretty much like a spar buoy to the
approaching tsunami.
• Unless man has modified the atoll, runup seems to be a factor of
two from the height of the tsunami on the open ocean compared to
a factor of five or six for open coasts on high islands.
• High islands have a tremendously reduced hazard if they have reefs
• By contrast, in 1960 Hawaii saw about 3 meters on open coasts
without focusing and numerous locations where runup approached
10 meters (in Hilo runup reached 11 meters and 61 people died).
Source: Gerard Fryer at the NOAA Pacific
Tsunami Warning Center

17. Meters
0.5
1.5
0
1
2
-0.5
-1
10:24
10:26
10:28
10:30
10:32
10:34
10:36
10:38
10:40
10:42
10:44
10:46
10:48
10:50
10:52
10:54
10:56
10:58
11:00
11:02
11:04
11:06
11:08
11:10
11:12
11:14
11:16
11:18
11:20
11:22
11:24
11:26
11:28
11:30
11:32
11:34
11:36
11:38
11:40
90 Minute elapsed time
11:42
11:44
NOAA Tidal Data: Midway 3-11-11
11:46
11:48
11:50
11:52
11:54

43. Estimated Loss of Life
• 110,000 Albatross chicks died out of 450,000
nesting pairs, impact will be most evident in 4-5
yrs when this vintage will begin mating
• 2,000 adult Albatross
• Virtually all underground nesting Bonin Petrils
that were located in the overwash zone
• Majority of plant life where seawater inundation
• The first chick from a mating pair of Short Tail
Albatross survived tsunami and 2 winter storms
• Minimal documented loss of marine life

44. Kure and Laysan Evacuees

45. Photo Credits to
• Chris Jordan www.midwayjouney.com
• Jan Vozenilek www.janvozenilek.com
• Wayne Sentman
http://web.mac.com/naturefinder
• Peter Leary http://peteatmidway.blogspot.com/
• Mike Daak www.midway-island.com
• James Watt http://www.wattstock.com/
• Ku`uipo Rossiter
• Byron Washom bwashom@ucsd.edu

46. The End