The Maldives:

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The Maldives Sea-levels, Tsunamis and Coastal
change Sue Dawson Niklas Mörner
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Islands are no more than 1.5 m above sea level
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The Maldives
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Satellite photo of the Atolls making up the
Maldives
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Some 1200 islands
Welcome to the Maldives
Grouped in some 20 larger atolls
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Queens Bath (Hithadoo Island, Addoo Atoll)

• Shore terrace 400800 BP 60 cm
• High-tide level 17901970 20-30 cm
• High-tide level today
• (1) Mean-tide level today

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• A sea level fall 1970-1975
• lowering of the erosion level
• building out of lower shoreplane
• owergrowing of old surface
• weathering of old surface
• The lowering was in the order of
• 20-30 cm
• (probably an effect of increased evaporation,
  decreased precipita-tion and/or changed monsoonal
  regime)

The Maldives, 2002
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Example of records of short high sea levels. This
coral, today 5-10 cm above mean zero, and in
situ requites a water depth of 60 cm (according
to Laborel), implying a higher sea level of
about 70 cm.
The coral is cut and dated at 2 levels. (2)
1585 35 BP (1) 1635 35 BP
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Goidhoo Atoll
Fen cores
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Sea level oscillations in the last millennium
(cores from two fens) The 2 swamps became lakes
in 1790 and both dried up in 1970
NB. Peat and shell dates differ by 350 years, a
good measure of the local sea correction
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The new sea level curve of the Maldives (Mörner,
2007) recording a number of oscillations driven
by the redistribution of ocean water masses. The
base line seems to peak at around 1300 BP
(excluding any Mid-Holocene maximum as predicted
by the loading models).
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The combined observational records (in mm/year)
for the last 300 years. It shows variations ups
and downs but no trend. For year 2100, INQUA
gives predictions in line with this
record, whilst the IPCC scenarios lie far above
way off observational data
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The flooding scenario of IPCC does not concur
with observational sea level facts. Therefore, it
must be called-off as a mistake. Today, we favour
a 2100 value of 5 cm 15 cm
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The Maldives
Earthquake Epicentre 2500 km 3 hrs travel time
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Satellite image 2 hrs after the earthquake
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Tide data for Male and Gan
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The Maldives

• Population 290,000
• Total number of islands 1,192
• Number of inhabited islands199
• Flooding Status
• Only 9 islands had no flooding
• 69 islands completely flooded

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Sand deposits across the airport
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Gan, Laamu Atoll Maldivestsunami sediment
thickness 30cm Finer sediment than the beach
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Particle Size Analysis
Well sorted beach sands differ From the overlying
tsunami deposits
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Isdhoo, Laamu Atoll, 2cm tsunami sediment And
PSA profiles
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Sediment plumes
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Sediment plumes across the islands protection of
the land from the reefs located up to 1km
offshore
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Clear sediment plumes into the lagoon
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Sediment plumes through to the lagoon inside the
atoll (distance c. 500m.)
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Coral debris plumes in the lee of trees and
vegetation
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Erosion scarp on the leeward side of the islands
Tsunami deposits Overlie the beach sands
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Male
Highly built up- Male Was severely flooded
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Sea level oscillations in the last millennium
(cores from two fens) The 2 swamps became lakes
in 1790 and both dried up in 1970
NB. Peat and shell dates differ by 350 years, a
good measure of the local sea correction
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Ostracod and Foraminifera
Spiroloculina
Quadracythere sp.
Quinqueloculina
Elphidium sp.
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Potential for chronology of extreme events
Laamu Atoll
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Table 1. Submarine shedding of sand into caves
with radiocarbon dating of shells and coral after
subtraction of 350 years for regional sea
correction.
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Tsunami in AD 1733 (1) in fen records (left),
(2) in submarine caves (right) and (3) in a
historical record of a disastrous flooding in
1733.
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The Lisbon earthquakeTsunami is classical and
similar events are bound to re-occur in the
near-future
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When a coastal segment experiences erosion, a
sea level rise is often advocated. The reality
is much more complicated in fact, a sea level
lowering generally causes more erosion! The clue
is often what actually is to be found on the
lee-side