Tsunami Damage to Coral Reefs in American Samoa

dfenner@blueskynet.as to coral-list 11/4/09

A team of researchers has been making rapid assessments of damage to coral
reefs in American Samoa from the tsunami of Sept 29, 2009. We have examined
about 37 sites so far. There is a wide range of damage, from no damage to
complete removal of one patch of coral. Sites with little or no damage are
more common than sites with heavy damage. Why some places were damaged much
more than others is something that will be examined in the coming months and
years. There is some debris on reefs from the damage on land, but the heaviest
accumulation is likely at the head of the harbor, where there were no reefs.
Efforts to remove debris are underway, with cars being removed from the harbor,
debris removed from villages, streams and beaches, and rags being removed from
young table corals at the one known location where this is common.
On land as well as in the water, it is clear that the tsunami damaged
sites on the north shore as well as the south shore, even though the earthquake
was to the southwest. Computer models predict this correctly.
On land this was a tragedy with loss of life, but training about what to
do in case of a large earthquake had been going on since the Ache earthquake
and tsunami in Indonesia, and many, many lives were saved by villagers knowing
to run uphill after a large earthquake. We have those involved in that
training to thank for the fact that so many lives were saved that would
otherwise been lost.
It is good to keep in mind that this is a natural event. It has happened
here many times before (though not for many decades with such power), and will
happen again. Even if tsunamis this big only happened once in 150 years, the
island of Tutuila is 1.5 million years old, so it would have happened 10,000
times before. The reefs recovered and grew back, or else there would be none
left today. As long as humans have not impacted the reef so as to reduce
resilience, the reefs should recover from this. Although such events are very
dramatic, they are dwarfed in importance to the world’s reefs by the insidious
effects of humans, in particular the looming threat of climate change, which
will likely dwarf previous human impacts.

For the reef assessment team:

Douglas Fenner, Domingo Ochavillo, Lucy Jacob
Dept of Marine & Wildlife Resources of American Samoa (DMWR)

Paul Brown, Jim Nimz
National Parks of American Samoa

For the DMWR reef cleanup team:
Alice Lawrence and many volunteers

And all the support staff, and the support of the agencies

There have also been a whole series of teams of experts on tsunamis from USGS
(U.S. Geological Survey) and Japan, surveying the extent of inundation on land,
and some underwater topography, to understand what happened and why. Such
effort will hopefully continue. Similar teams have been working in
(independent) Samoa, where the island of Upolu was hit very hard.

Also, a team from the American Samoa Coral Reef Advisory Group surveyed damage
on land in many villages, including debris in streams, on beaches, and on the
reef flats. Damaged vehicles likely leaked fluids, but there have been no
major chemical spills discovered so far to our knowledge.

There have been both huge efforts by the villagers to recover from this, but
also an outpouring of aid and effort, from FEMA (Federal Emergency Management
Agency), NGO’s, foreign governments, businesses, church groups, and
individuals. Our airport has been the busiest it has ever been with a steady
stream of air force transport planes bringing in generators and other supplies,
and Hawaiian Airlines has brought down plane loads of volunteers and supplies.
The world’s largest transport plane, a Russian-built jet with 3 engines on each
wing, brought ten, 27,000 pound generators in a single flight. The aid has
been deeply appreciated here. We hope similar aid has been sent to (independent)
Samoa, where the need is likely even greater. There are people here who have
been traumatized, and a team has been working to help with that. People have
been deeply touched by all the help. Electricity is back on most places, and
people are putting their lives back together.


USGS reports:
http://walrus.wr.usgs.gov/news/field.html

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