Coastal Hazards: Geological Perspectives
from the U.S. Atlantic Coast
Ilya Buynevich Temple University, USA
N. Asp, P. Souza Filho
R. Angulo
W. Cleary
D. FitzGerald A. Bitinas
D. Pupienis
R. McBride
R. Goble
R. Ballard
S. van Heteren
M. Fenster
Collaborators
Hurricane
Katrina
(2005)
July 2001
Aug 2005
Chandeleur Islands, LA
USGS Coastal and Marine Geology Program
- Erosion
- Flooding
- Submergence
U.S. Atlantic
& Gulf Coasts
>$3 trillion
Hurricane
Sandy
(2012)
Seaside Heights, NJ
USACOE
Seaside Heights, NJ
USACOE
Beach NourishmentBeach Nourishment
1414
•• enough sandenough sand•• same or coarsersame or coarser•• after stormsafter storms
U.S. Army Corps of Engineers
(USACOE) Offshore breakwatersOffshore breakwaters
1313
tombolo tombolo effecteffect
U.S. Atlantic
& Gulf Coasts
>$3 trillion
Deposition
(sand invasion)
Ingleses, Brazil
Desert dunes, Mauritania
Baltic Sea coast Dune Village, Silver Lake, Michigan
1. What are the stability thresholds for sandy coasts?
- signatures of erosion – timing and hindcasting
- quantitative analysis of wave climate and storm-surge parameters
- response to accelerated sea-level rise and increased storminess
2. How do old channels affect coastal behavior?
- subsurface anomalies within coastal sequences
- vulnerability of barrier segments to breaching
- tidal prism reconstruction and sea-level change
3. Dune reactivation phases: causes and timing
- climatic vs. internal triggering mechanisms
- paleo-wind reconstruction (102-103 yr)
- human-landscape interaction
NEW FRONTIERS
Recognition and Dating of Erosion in Sand-Dominated Systems
Questions and Challenges
SEVERE SEA FLOODSNorth Sea and English Channel
Medieval Warm
Period
RELIABLE HISTORICAL ACCOUNTS
Europe
North America
1000 1400 1800 800AD 1200 1600 2000AD
Little Ice Age
from Lamb (1995)
Temperature( C)
Numberof
floods
15
10
5
0
11
10
9
8
ANNUAL TEMPERATURECentral England
South America from S. de Champlain (1605)
60-95%
vertical resolution
0
1 mm
1 cm
10 cm
1 m
10 m
1 km
10 km
100 m
1 mm 1 cm 10 cm 1 m 10 m 100 m 1 km 10 km
deepseismic
shallowseismic
reflection
GPR(120 MHz)
vibracoringscope of
coastal-stratigraphicresearch
pulse-augercoring
wash-borecoring
high-resolutionstratigraphy
Field Techniques
GPR
200 MHz
resolution
pe
ne
tra
tio
n d
ep
th
High-Resolution Geophysics
Groundtruth
Field Techniques
Research Sites
Active projects
Outside collaborator
Ukraine
Lithuania
Kuwait
India
Alaska
New England
VA,NC,SC
Pará, Brazil
Santa Catarina,
Brazil
New Mexico NJ,PA,MD Israel
Turkey
Texas Bahamas
Part 1
Erosion: Signatures and Chronology
Progradation: Deposition - Erosion
photo by P. Brown (Rocky Mountain Tree-Ring Research)
tree rings
From Ebernards et al (2006)
Ground-Penetrating Radar (GPR)
Revolutionized coastal geological research: Continuous high-resolution imaging
- physical structures
- textural contrast
- composition
(+ iron oxides,
clays, organics)
- moisture content
- bulk density
- porosity
Layer 1
Layer 2
200 MHz antenna
control unit
electromagnetic waves
Causes of reflection:
Signal loss: - saltwater, thick clay, metal
South Waihi Beach, New Zealand
HMC
buried HMCs
Heavy-Mineral Concentrations (HMCs) proxies for high-energy events
photos by T. Hume
HMC
Superstorm Sandy
(2012)
Erosion: Events and Signatures
Hurricanes/Typhoons Cyclones Extra-tropical storms
Beach/dune scarps HMC Surge channels
Tsunamis
NASA/Digital Globe images
2004 tsunami (photo by Rob Evans)
1978 storm scarp ocean
Punctuated Progradation Hunnewell Beach, Maine
Silver Lake MAINE
70
45
47
68 67
44
43
47
4646
71
45
44
1983
1978 scarp
photo by D.M. FitzGerald
Relict erosional scarps (no geomorphic evidence)
5 mm
Optically-Stimulated Luminescence (OSL) Dating
Buynevich et al. (2007)
recent
scarp
dunes:
167±13
1,545±170 391±36 287±27
153±17 years BP (1635)
(1815)
45±15
5,600-5,000 BP
3,580-3,380 BP
cal 14C ages
Storm Chronology and Climate Links ocean
photo by K. Fink
5 m
3
0
depth
(m
)
391±36 287±27 yBP
(1635 Hurricane)
S1
S4
S3
S2
Paleo-scarp interval vs. time
Visbeck et al (2001)
Atlantic Hurricane Tracks (1980-2005)
(HRC/NASA)
post-storm sandbars
paleo-scarp interval (dS)
Part 2
Paleo-Channels: Geological Legacy
Transgressive Coastlines
Long Island, NY (photo by Covello & Terchunian)
Landward transfer of sand during storms:
integral to barrier migration
with sea-level rise
(modified after John Norton)
flood-tidal delta
washovers
breach
LANDWARD SAND TRANSFER
GEOHAZRD
Superstorm Sandy
(2012)
20031977193818861846
GPR only
20031977193818861846
GPR only
Erosion is NOT uniform
N
1 km
Average shoreline retreat (m/yr) over 150 years (MCZM data)
0.5
1.0
0
Channel fill:
>60%
longshore transport
Inlet History
Falmouth, MA
Cape Cod, Massachusetts
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0 20 40 60 80 100 120 140 160
Channel Dimensions
Minimum bank-full width (m)
mean tidal
range
N=21
dredged
annually
GPR only
historic
present (stabilized)
w
d
Falmouth south shore
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0 20 40 60 80 100 120 140 160
Channel Dimensions
Minimum bank-full width (m)
mean tidal
range
N=21
dredged
annually
GPR only
historic
present (stabilized)
w
d
Falmouth south shore
Vineyard Sound
stabilized
channel
sand plug
Paleo-channel Research
1846
1997
Hurricane Bob
washover
(1991)
Buynevich (2003)
relict channel
Menauhant Beach, Cape Cod, MA
relict
feature
Providence, RI – 23 September 1815
The Great September Gale of 1815
Reconstructed damage – Fujita Scale (courtesy E. Boose – Harvard Forest)
New Currituck Inlet
(1713-1828)
storm breach
Old Currituck Inlet
(<1585 -1731)
20 mchannel-bottom reflection
~10 m
dune sands
CHANNEL
MIGRATION
N S
last position
VA
NC
Roanoke, NC (1584)
Old Currituck Inlet Paleo-channel
Tidal Prism
Reconstruction
Oceanic Inlets (Jarrett, 1976)
Ac = 6.954x10-6Ω1.14
20 mchannel-bottom reflection
~10 m
dune sands
CHANNEL
MIGRATION
N S
Ω Ac
Paleo-tidal prism:
Ω=9.6x106m3
Ω=1.5x106m3
last position
VA
NC
New Currituck Inlet
(1713-1828)
storm breach
Old Currituck Inlet
(<1585 -1731)
Part 3
Dunes as Archives of Climate Change and Human-Landscape Interaction
Coastal Dune Research
- Activity through Holocene
- Global distribution
- Sensitivity to environmental changes
Record of:
- wind patterns (GCM groundtruth)
- wind velocity
- sea-level change
- sediment supply
- precipitation/water table elevation
- vegetation dynamics
- recent human activities
Major Dunefields
Reactivated Dunes
buried
forest
OSL
~1m
5m
Atlantic Ocean
dune migration
Basin-Scale Links Baltic Sea
Cape Cod, Massachusetts
- NAO-sensitive regions
- similar SL history, climate, vegetation
- different history of human activities
Ongoing research: - Landscape change (6,000 – present)
- N. Atlantic climate: 102-103-yr shifts - Synchroneity of aeolian phases?
- Storminess – trigger of dune activity? - Natural vs. human-induced changes
Aquinnah Dunefield
Curonian Spit,
Lithuania Visbeck et al (2001)
Martha’s Vineyard
USA
GoogleEarth Image
Lithuania
Baltic
Sea
10 km
wind
Highest coastal dunes in Northern Europe
Russia
Curonian
Spit
STUDY
AREA
N
massive
(107-109 m3)
landward
sand
transfer
oversteepening
and collapse
dune migration
lagoon
lagoon
Baltic Sea
14 settlements buried by migrating dunes
Sand Invasion (14-19th centuries)
Advancing dunes(16-18th century)
Buried settlements ( relocation)
Modern townsGPR transect
(segment shown below)
North
Curonian Lagoon
Baltic Sea
Old Karvaičių II
(1740-1797)
Neolithic site
(~4.5 ka BP)
1 km
Buried settlements ( relocation)
Modern townsGPR transect
(segment shown below)
North
Curonian Lagoon
Baltic Sea
Old Karvaičių II
(1740-1797)
Neolithic site
(~4.5 ka BP)
1 km
Neringa
Outcrop/core studies – limited information
water
table
Paleosols – Chronology & Landscape Stability
16
0
Baltic Sea
water table
deflation surface (25 m above MSL)
Russia
Lithuania
deflation remnant
33o
Paleosol
P1 P2
0 5 10 m
De
pth
(m
)
20 km deflation surface
Naglių
Nature Reserve
Range: 300 ns Vertical Resolution: 16-18 cm
230
0
Tw
o-w
ay tra
vel tim
e (n
s)
P3
exposed paleosol P1
dune slipfaces
dune migration
GPR profileMS profile
Paleosols:exposedburied
P1P2P3
P4
P1
0 50 m 100
Baltic Sea(1700 m)
Curonian Lagoon(200 m)
GPR profile
P1
paleo-dunemigration
vegetateddune
ds
dr
drds
ds
deflationremnant
(dr)
CuronianLagoon
BalticSea
Nida
Juodkrante
5 km
N
Lithuania
Russia
C
wind
Radiocarbon and OSL Chronology (cal yBP)
3,355±115 1,255±8
5
5,690±80
700±40 Little Ice Age
begins
14C
OSL 5,243±33
0
3,893±21
0
1,283±80 163±20
Activity-Stability Phases
Phase 1: ~5,700 cal BP
Phases 2-4: 3,400-700 cal BP
Phase 5: post-700 cal BP
(Little Ice Age)
P4
P4 P3 P2
P1
deflation
buried paleosols
soil
soil
P4 P3 P2 P1 Similar evolution:
Łeba dunes, Poland (Borówka, 1975)
Cape Flattery dunes, Queensland, Australia (Pye, 1993)
Age of spit
> 6 ka
burial
with SL rise
Reactivation of aeolian activity: Triggers
charcoal
Storms, disease, deforestation
Fires (natural and man-made)
P1
P1
Buried Landscapes and Structures
7 m
0
water table
ground surface
hyperbolics
dune migration
200 MHz
buried structures?
tree root
buried utilities
Curonian Spit
0 5 10 m
5 m
lagoon
dune surface
dune migration
Human-Landscape Interaction
buried occupation
surface
GPR near Old Karvaičių II
(1700-1797)
Buried settlements ( relocation)
Modern townsGPR transect
(segment shown below)
North
Curonian Lagoon
Baltic Sea
Old Karvaičių II
(1740-1797)
Neolithic site
(~4.5 ka BP)
1 km
Buried settlements ( relocation)
Modern townsGPR transect
(segment shown below)
North
Curonian Lagoon
Baltic Sea
Old Karvaičių II
(1740-1797)
Neolithic site
(~4.5 ka BP)
1 km
~15 m
0
Summary Extreme Events – key mechanism of landward sand transfer
Integrated approach:
- onshore-offshore geophysics
- groundtruth: deep cores (5-10 m in sand)
- multi-dating techniques
New opportunities to reconstruct and quantify:
- Beach/shoreface gradients (texture/depth/wave energy)
- Extent and chronology of erosion (storm impact)
- Quantitative storm hindcasting based on geological indicators
- Shoreline retreat rates (vulnerability to SL rise)
- Channel distribution (onshore-offshore links, stability)
- Channel dimensions (tidal prism, longshore transport)
- Dune stratigraphy (regional climate, sediment supply, sand invasion)
Paldies ~ Thank You
Research Support