Submarine platform development by erosion of a Surtseyan cone at Capelinhos, Faial Island, Azores
Erosion of volcanic islands ultimately creates shallow banks and guyots, but the ways in which erosion proceeds to create them over time and how the coastline retreat rate relates to wave conditions, rock mass strength and other factors are unclear. The Capelinhos volcano was formed in 1957/58 durin...
Published in: | Earth Surface Processes and Landforms |
---|---|
Main Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2019
|
Subjects: | |
Online Access: | https://archimer.ifremer.fr/doc/00590/70196/70234.pdf https://doi.org/10.1002/esp.4724 https://archimer.ifremer.fr/doc/00590/70196/ |
id |
ftarchimer:oai:archimer.ifremer.fr:70196 |
---|---|
record_format |
openpolar |
spelling |
ftarchimer:oai:archimer.ifremer.fr:70196 2023-05-15T17:36:43+02:00 Submarine platform development by erosion of a Surtseyan cone at Capelinhos, Faial Island, Azores Zhao, Zhongwei Mitchell, Neil C. Quartau, Rui Tempera, Fernando Bricheno, Lucy 2019-12 application/pdf https://archimer.ifremer.fr/doc/00590/70196/70234.pdf https://doi.org/10.1002/esp.4724 https://archimer.ifremer.fr/doc/00590/70196/ eng eng Wiley info:eu-repo/grantAgreement/EC/FP7/213144/EU//CORALFISH info:eu-repo/grantAgreement/EC/FP7/228344/EU//EUROFLEETS https://archimer.ifremer.fr/doc/00590/70196/70234.pdf doi:10.1002/esp.4724 https://archimer.ifremer.fr/doc/00590/70196/ info:eu-repo/semantics/openAccess restricted use Earth Surface Processes And Landforms (0197-9337) (Wiley), 2019-12 , Vol. 44 , N. 15 , P. 2982-3006 submarine platform coastal erosion Surtseyan eruption wave attenuation Azores text Publication info:eu-repo/semantics/article 2019 ftarchimer https://doi.org/10.1002/esp.4724 2021-09-23T20:33:49Z Erosion of volcanic islands ultimately creates shallow banks and guyots, but the ways in which erosion proceeds to create them over time and how the coastline retreat rate relates to wave conditions, rock mass strength and other factors are unclear. The Capelinhos volcano was formed in 1957/58 during a Surtseyan and partly effusive eruption that added an ~2.5 km2 tephra and lava promontory to the western end of Faial Island (Azores, central North Atlantic). Subsequent coastal and submarine erosion has reduced the subaerial area of the promontory and created a submarine platform. This study uses historical information, photos and marine geophysical data collected around the promontory to characterize how the submarine platform developed following the eruption. Historical coastline positions are supplemented with coastlines interpreted from 2004 and 2014 Google Earth images in order to work out the progression of coastline retreat rate and retreat distance for lava‐ and tephra‐dominated cliffs. Data from swath mapping sonars are used to characterize the submarine geometry of the resulting platform (position of the platform edge, gradient and morphology of the platform surface). Photographs collected during SCUBA and ROV dives on the submarine platform reveal a rugged surface now covered with boulders. The results show that coastal retreat rates decreased rapidly with time after the eruption and approximately follow an inverse power‐law relationship with coastal retreat distance. We develop a finite‐difference model for wave attenuation over dipping surfaces to predict how increasing wave attenuation contributed to this trend. The model is verified by reproducing the wave height variation over dipping rock platforms in the UK (platform gradient 1.2° to 1.8°) and Ireland (1.8°). Applying the model to the dipping platform around Capelinhos, using a diversity of cliff resistance predicted from known lithologies, we are able to predict erosion rate trends for some sectors of the edifice. We also explore wider implications of these results, such as how erosion creates shallow banks and guyots in reef‐less mid‐oceanic archipelagos like the Azores. Article in Journal/Newspaper North Atlantic Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Earth Surface Processes and Landforms 44 15 2982 3006 |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
topic |
submarine platform coastal erosion Surtseyan eruption wave attenuation Azores |
spellingShingle |
submarine platform coastal erosion Surtseyan eruption wave attenuation Azores Zhao, Zhongwei Mitchell, Neil C. Quartau, Rui Tempera, Fernando Bricheno, Lucy Submarine platform development by erosion of a Surtseyan cone at Capelinhos, Faial Island, Azores |
topic_facet |
submarine platform coastal erosion Surtseyan eruption wave attenuation Azores |
description |
Erosion of volcanic islands ultimately creates shallow banks and guyots, but the ways in which erosion proceeds to create them over time and how the coastline retreat rate relates to wave conditions, rock mass strength and other factors are unclear. The Capelinhos volcano was formed in 1957/58 during a Surtseyan and partly effusive eruption that added an ~2.5 km2 tephra and lava promontory to the western end of Faial Island (Azores, central North Atlantic). Subsequent coastal and submarine erosion has reduced the subaerial area of the promontory and created a submarine platform. This study uses historical information, photos and marine geophysical data collected around the promontory to characterize how the submarine platform developed following the eruption. Historical coastline positions are supplemented with coastlines interpreted from 2004 and 2014 Google Earth images in order to work out the progression of coastline retreat rate and retreat distance for lava‐ and tephra‐dominated cliffs. Data from swath mapping sonars are used to characterize the submarine geometry of the resulting platform (position of the platform edge, gradient and morphology of the platform surface). Photographs collected during SCUBA and ROV dives on the submarine platform reveal a rugged surface now covered with boulders. The results show that coastal retreat rates decreased rapidly with time after the eruption and approximately follow an inverse power‐law relationship with coastal retreat distance. We develop a finite‐difference model for wave attenuation over dipping surfaces to predict how increasing wave attenuation contributed to this trend. The model is verified by reproducing the wave height variation over dipping rock platforms in the UK (platform gradient 1.2° to 1.8°) and Ireland (1.8°). Applying the model to the dipping platform around Capelinhos, using a diversity of cliff resistance predicted from known lithologies, we are able to predict erosion rate trends for some sectors of the edifice. We also explore wider implications of these results, such as how erosion creates shallow banks and guyots in reef‐less mid‐oceanic archipelagos like the Azores. |
format |
Article in Journal/Newspaper |
author |
Zhao, Zhongwei Mitchell, Neil C. Quartau, Rui Tempera, Fernando Bricheno, Lucy |
author_facet |
Zhao, Zhongwei Mitchell, Neil C. Quartau, Rui Tempera, Fernando Bricheno, Lucy |
author_sort |
Zhao, Zhongwei |
title |
Submarine platform development by erosion of a Surtseyan cone at Capelinhos, Faial Island, Azores |
title_short |
Submarine platform development by erosion of a Surtseyan cone at Capelinhos, Faial Island, Azores |
title_full |
Submarine platform development by erosion of a Surtseyan cone at Capelinhos, Faial Island, Azores |
title_fullStr |
Submarine platform development by erosion of a Surtseyan cone at Capelinhos, Faial Island, Azores |
title_full_unstemmed |
Submarine platform development by erosion of a Surtseyan cone at Capelinhos, Faial Island, Azores |
title_sort |
submarine platform development by erosion of a surtseyan cone at capelinhos, faial island, azores |
publisher |
Wiley |
publishDate |
2019 |
url |
https://archimer.ifremer.fr/doc/00590/70196/70234.pdf https://doi.org/10.1002/esp.4724 https://archimer.ifremer.fr/doc/00590/70196/ |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Earth Surface Processes And Landforms (0197-9337) (Wiley), 2019-12 , Vol. 44 , N. 15 , P. 2982-3006 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/213144/EU//CORALFISH info:eu-repo/grantAgreement/EC/FP7/228344/EU//EUROFLEETS https://archimer.ifremer.fr/doc/00590/70196/70234.pdf doi:10.1002/esp.4724 https://archimer.ifremer.fr/doc/00590/70196/ |
op_rights |
info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.1002/esp.4724 |
container_title |
Earth Surface Processes and Landforms |
container_volume |
44 |
container_issue |
15 |
container_start_page |
2982 |
op_container_end_page |
3006 |
_version_ |
1766136299154046976 |