RISE poster
Undergraduate Category: Physical and Life Sciences Degree Level: Undergraduate Abstract ID# 461
COMPARING THE SEDIMENT SIGNATURE OF HURRICANE SANDY WITH HISTORIC AND PREHISTORIC STORM DEPOSITS Stromer, Zachary (1), Donnelly, Jeffrey (2), Madsen, Stephanie (2), and Sullivan, Richard (2), (1) Department of Marine and Environmental Sciences, Northeastern University, 360 Huntington Ave, Boston, MA 02115, [email protected], (2) Geology & Geophysics Department, Woods Hole Oceanographic Institution, MS #22, 360 Woods Hole Rd, Woods Hole, MA 02543 Abstract
Crab Meadow, Long Island
Hurricane Sandy (2012) presented an example of the destructive potential of hurricanes. Studies of changes in the frequency of such storms can provide insights that allow for better understanding the climatic forcing of intense hurricane activity. However, this effort is impeded by the lack of data; reliable records of major hurricane strikes reaches only to the 19th century. Thus, finding patterns in changes in storm frequencies is extremely difficult. By contrast, the sedimentological record can extend the historic record back thousands of years.
Coring Sites
0.04
0.03
North
Carbon 14 Dates
1893?
50
1821? Google earth. September19th, 2013.
1788?
Cores collected through vibracoring • Coarse % determined through sieving at 63 microns every 1 cm • Organics measured and eliminated through LOI techniques • Cesium 137 measured by Canberra GL2020RS high-purity germanium gamma detectors • Radiographs obtained using an Itrax XRF Corescanner • C14 dates obtained through NOSAMS facility
1693?
100
Lighter tones represent denser/coarser material Storm deposits matched between cores
Marsh tempestites with vibracore setup 0
CMSN1 1:3
CMSN2 1:3
CMSN3 1:2
CMSN4 1:2
Depth (cm)
Correlated Core Radiographs
Paleotempestology
1370 AD 150
200
20
Sandy Storm Surge Heights and Post Sandy Coring Locations
30
1893?
?
40
21 18
8?
60
1821?
250
70
178
Depth (cm)
50
80
300
1788? 90
1693?
100
110
1693?
350
120
1464 AD
130
140
Carbon-14 dates. Obtained through National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS). Depth (cm)
Lab #
Core
OS-104768
CMSN1
137
OS-104767
CMSN1
OS-104765
CMSN2
C Age
1σ Calender ages (yrs B1950) Calibrated using Calib 6.1.0 [Reimer et al., 2009] (probability)
Cal age* (years before 1950)
Cal age (AD)
Material
560±20
538 – 555 (0.584623) 608 – 623 (0.415377)
580.5
1369.5
Plant/wood
307
1870±30
1740 – 1756 (.14863) 1780 – 1800 (.183505) 1810-1868 (0.667865)
1839
111
Plant/wood
130
405±25
467 – 506 (1.)
486.5
1463.5
Plant/wood
14
* Cal age calculated by taking mean of bolded 1σ dates.
10
are sites with no evidence of sandy overwash deposit are sites with overwash deposits
0.02
1963 AD
•
Typical Barrier beach
0.01
0
Methods and Materials
Storm surge event with dune breach.
0
CMSN3
Cs-137 (bq/g) 100%
CMSN4
CMSN2
50%
No surface layers corresponding to Hurricane Sandy were present in any of the initial sediment cores collected. This indicates that overwash fans from Hurricane Sandy are rare in backbarrier environments. However, evidence of numerous other historic events is prevalent throughout a number of the cores. In particular, overwash deposits associated with the 1821 hurricane are present in nearly all study sites. Thus, we hypothesize that large, slow-moving, but relatively weak storms such as Sandy may be less likely to leave deposits than smaller sized storms with stronger winds and higher waves. Cores from Crab Meadow, Long Island were analyzed and an age model is being established based on these cores to constrain the chronology of the intense storms affecting this region. Computer modeling using NOAA’s SLOSH simulation provides local storm-surge data for storms in this record and is used to estimate the power of some of these more modern events. Few storm-event layers are identified in the Crab Meadow cores between approximately 500 and 1000 B.P., which closely matches similar quiescent periods recorded for this region in earlier studies.
Percent > 63 µm 0%
CMSN1
(NOAA Sea, Lake, and Overland Surges from Hurricanes model)
Percentage of sand fraction in core CMSN1 1:3 – 3:3 Dates in red are C14 and Cs137 ages Dates in black are interpreted historic storm tempestites
Locations of cores used in this study
In order to compare the effects of Hurricane Sandy to historic and pre-historic storms in the region, we collected nearly 30 vibracores from the New York and New Jersey region in the immediate aftermath of the storm. Target coring locations were chosen to maximize the likelihood of capturing sediments deposited by Sandy. Cores were analyzed (LOI, grain-size analysis), and coarse sediment layers were identified as storm proxies. Chronology was established using both radiocarbon dating and 137Cs (a product of nuclear weapons testing) dating techniques.
SLOSH model of 1821 storm
Coarse fraction stratigraphy and dating of of CMSN1
1370 AD
150
Acknowledgements: This work could not have been accomplished without the help and support of the entire coastal systems group lab at WHOI, as well as the endless guidance and patience of Northeastern professor, Richard Bailey. Their willingness to give of their time has been very much appreciated. I would also like to thank Woods Hole Oceanographic Institute for their funding of this project and Northeastern University for supporting this research.
111 AD
Conclusion As a result of this work it was noted that Hurricane Sandy left no appreciable overwash deposits on the surface of Crab Meadow. Cores collected from Crab Meadow did contain sand layers predating Hurricane Sandy that provide a proxy for pre-historic storm events. Possible explanations as to the lack of Sandy Related Deposits are: • Intensive armoring, developments, and roads construction along much of the Coastline. • The wind direction of Sandy relative to Crab Meadow (Though these two explanations do not explain the region-wide lack of deposits) • The reduced wave climate relative to stronger storms It is more likely that the absence of coarse-grained deposits from Hurricane Sandy is a result of the slow moving nature of the storm. Despite having a large radius and producing a significant storm surge Sandy’s slow speed did not promote as large a wave climate as those generated by stronger storms. It appears that both high water levels and an intense wave climate are required to breach dunes and allow for the widespread deposition of overwash fans. Surge modelling only provides part of the story. In order to better characterize the depositional nature of a storm, wave models need to be incorporated with future research involving not just SLOSH, but also ADCIRC and SWAN. Hurricane Sandy was a large storm that caused tremendous damage but also taught us about the impact of large storms. • The extent of the damage Sandy caused was a result of a large population/extensive infrastructure situated along a vulnerable coastline • Events such as Sandy are not rare in either the historic or geologic record • Not all storms will be recorded as sand horizons at all locations o By looking at many cores over a large geographical region, we can establish regional patterns of storm range and frequency In looking at such patterns we can get a feeling of the size of large storms such as a hurricane in 1821 that is evident over a large region in many cores, and is noted in the historic record as being particularly large. We can also note the presence of a quiescent period in intense events is evident between 500 and 1000 B.P. in our core as has been noted in previous studies of the region. With rising sea levels along the Northeast coastline coupled with increasing development and human population growth, it is evident that storms like Sandy are likely to be an increasing hazard in the future.
COMPARING THE SEDIMENT SIGNATURE OF HURRICANE SANDY WITH HISTORIC AND PREHISTORIC STORM DEPOSITS Stromer, Zachary (1), Donnelly, Jeffrey (2), Madsen, Stephanie (2), and Sullivan, Richard (2), (1) Department of Marine and Environmental Sciences, Northeastern University, 360 Huntington Ave, Boston, MA 02115, [email protected], (2) Geology & Geophysics Department, Woods Hole Oceanographic Institution, MS #22, 360 Woods Hole Rd, Woods Hole, MA 02543 Abstract
Crab Meadow, Long Island
Hurricane Sandy (2012) presented an example of the destructive potential of hurricanes. Studies of changes in the frequency of such storms can provide insights that allow for better understanding the climatic forcing of intense hurricane activity. However, this effort is impeded by the lack of data; reliable records of major hurricane strikes reaches only to the 19th century. Thus, finding patterns in changes in storm frequencies is extremely difficult. By contrast, the sedimentological record can extend the historic record back thousands of years.
Coring Sites
0.04
0.03
North
Carbon 14 Dates
1893?
50
1821? Google earth. September19th, 2013.
1788?
Cores collected through vibracoring • Coarse % determined through sieving at 63 microns every 1 cm • Organics measured and eliminated through LOI techniques • Cesium 137 measured by Canberra GL2020RS high-purity germanium gamma detectors • Radiographs obtained using an Itrax XRF Corescanner • C14 dates obtained through NOSAMS facility
1693?
100
Lighter tones represent denser/coarser material Storm deposits matched between cores
Marsh tempestites with vibracore setup 0
CMSN1 1:3
CMSN2 1:3
CMSN3 1:2
CMSN4 1:2
Depth (cm)
Correlated Core Radiographs
Paleotempestology
1370 AD 150
200
20
Sandy Storm Surge Heights and Post Sandy Coring Locations
30
1893?
?
40
21 18
8?
60
1821?
250
70
178
Depth (cm)
50
80
300
1788? 90
1693?
100
110
1693?
350
120
1464 AD
130
140
Carbon-14 dates. Obtained through National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS). Depth (cm)
Lab #
Core
OS-104768
CMSN1
137
OS-104767
CMSN1
OS-104765
CMSN2
C Age
1σ Calender ages (yrs B1950) Calibrated using Calib 6.1.0 [Reimer et al., 2009] (probability)
Cal age* (years before 1950)
Cal age (AD)
Material
560±20
538 – 555 (0.584623) 608 – 623 (0.415377)
580.5
1369.5
Plant/wood
307
1870±30
1740 – 1756 (.14863) 1780 – 1800 (.183505) 1810-1868 (0.667865)
1839
111
Plant/wood
130
405±25
467 – 506 (1.)
486.5
1463.5
Plant/wood
14
* Cal age calculated by taking mean of bolded 1σ dates.
10
are sites with no evidence of sandy overwash deposit are sites with overwash deposits
0.02
1963 AD
•
Typical Barrier beach
0.01
0
Methods and Materials
Storm surge event with dune breach.
0
CMSN3
Cs-137 (bq/g) 100%
CMSN4
CMSN2
50%
No surface layers corresponding to Hurricane Sandy were present in any of the initial sediment cores collected. This indicates that overwash fans from Hurricane Sandy are rare in backbarrier environments. However, evidence of numerous other historic events is prevalent throughout a number of the cores. In particular, overwash deposits associated with the 1821 hurricane are present in nearly all study sites. Thus, we hypothesize that large, slow-moving, but relatively weak storms such as Sandy may be less likely to leave deposits than smaller sized storms with stronger winds and higher waves. Cores from Crab Meadow, Long Island were analyzed and an age model is being established based on these cores to constrain the chronology of the intense storms affecting this region. Computer modeling using NOAA’s SLOSH simulation provides local storm-surge data for storms in this record and is used to estimate the power of some of these more modern events. Few storm-event layers are identified in the Crab Meadow cores between approximately 500 and 1000 B.P., which closely matches similar quiescent periods recorded for this region in earlier studies.
Percent > 63 µm 0%
CMSN1
(NOAA Sea, Lake, and Overland Surges from Hurricanes model)
Percentage of sand fraction in core CMSN1 1:3 – 3:3 Dates in red are C14 and Cs137 ages Dates in black are interpreted historic storm tempestites
Locations of cores used in this study
In order to compare the effects of Hurricane Sandy to historic and pre-historic storms in the region, we collected nearly 30 vibracores from the New York and New Jersey region in the immediate aftermath of the storm. Target coring locations were chosen to maximize the likelihood of capturing sediments deposited by Sandy. Cores were analyzed (LOI, grain-size analysis), and coarse sediment layers were identified as storm proxies. Chronology was established using both radiocarbon dating and 137Cs (a product of nuclear weapons testing) dating techniques.
SLOSH model of 1821 storm
Coarse fraction stratigraphy and dating of of CMSN1
1370 AD
150
Acknowledgements: This work could not have been accomplished without the help and support of the entire coastal systems group lab at WHOI, as well as the endless guidance and patience of Northeastern professor, Richard Bailey. Their willingness to give of their time has been very much appreciated. I would also like to thank Woods Hole Oceanographic Institute for their funding of this project and Northeastern University for supporting this research.
111 AD
Conclusion As a result of this work it was noted that Hurricane Sandy left no appreciable overwash deposits on the surface of Crab Meadow. Cores collected from Crab Meadow did contain sand layers predating Hurricane Sandy that provide a proxy for pre-historic storm events. Possible explanations as to the lack of Sandy Related Deposits are: • Intensive armoring, developments, and roads construction along much of the Coastline. • The wind direction of Sandy relative to Crab Meadow (Though these two explanations do not explain the region-wide lack of deposits) • The reduced wave climate relative to stronger storms It is more likely that the absence of coarse-grained deposits from Hurricane Sandy is a result of the slow moving nature of the storm. Despite having a large radius and producing a significant storm surge Sandy’s slow speed did not promote as large a wave climate as those generated by stronger storms. It appears that both high water levels and an intense wave climate are required to breach dunes and allow for the widespread deposition of overwash fans. Surge modelling only provides part of the story. In order to better characterize the depositional nature of a storm, wave models need to be incorporated with future research involving not just SLOSH, but also ADCIRC and SWAN. Hurricane Sandy was a large storm that caused tremendous damage but also taught us about the impact of large storms. • The extent of the damage Sandy caused was a result of a large population/extensive infrastructure situated along a vulnerable coastline • Events such as Sandy are not rare in either the historic or geologic record • Not all storms will be recorded as sand horizons at all locations o By looking at many cores over a large geographical region, we can establish regional patterns of storm range and frequency In looking at such patterns we can get a feeling of the size of large storms such as a hurricane in 1821 that is evident over a large region in many cores, and is noted in the historic record as being particularly large. We can also note the presence of a quiescent period in intense events is evident between 500 and 1000 B.P. in our core as has been noted in previous studies of the region. With rising sea levels along the Northeast coastline coupled with increasing development and human population growth, it is evident that storms like Sandy are likely to be an increasing hazard in the future.
