Rainfall-triggered landslides in the Lisbon region over 2006 and relationships with the North Atlantic Oscillation
Landslides occurred in the Lisbon area during the last 50 years were almost always induced by rainfall and have been used to establish rainfall thresholds for regional landslide activity. In 2006, three new rainfall-triggered landslide events occurred in the study area, namely on the 20 March, the 2...
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ftdoajarticles:oai:doaj.org/article:72617509c2054765b3c3826f65454e4e 2023-05-15T17:32:05+02:00 Rainfall-triggered landslides in the Lisbon region over 2006 and relationships with the North Atlantic Oscillation J. L. Zêzere R. M. Trigo M. Fragoso S. C. Oliveira R. A. C. Garcia 2008-05-01T00:00:00Z https://doaj.org/article/72617509c2054765b3c3826f65454e4e EN eng Copernicus Publications http://www.nat-hazards-earth-syst-sci.net/8/483/2008/nhess-8-483-2008.pdf https://doaj.org/toc/1561-8633 https://doaj.org/toc/1684-9981 1561-8633 1684-9981 https://doaj.org/article/72617509c2054765b3c3826f65454e4e Natural Hazards and Earth System Sciences, Vol 8, Iss 3, Pp 483-499 (2008) Environmental technology. Sanitary engineering TD1-1066 Geography. Anthropology. Recreation G Environmental sciences GE1-350 Geology QE1-996.5 article 2008 ftdoajarticles 2022-12-31T08:51:20Z Landslides occurred in the Lisbon area during the last 50 years were almost always induced by rainfall and have been used to establish rainfall thresholds for regional landslide activity. In 2006, three new rainfall-triggered landslide events occurred in the study area, namely on the 20 March, the 25–27 October, and the 28 November. Landslide events occurred in March and October 2006 include shallow translational slides and few debris flows, and the corresponding absolute antecedent rainfall was found to be above the threshold for durations ranging from 4 to 10 days. These events also fit the combined threshold of daily precipitation and 5 days calibrated antecedent rainfall values. Likewise the landslide event that took place in late November 2006 includes some slope movements with deeper slip surfaces, when compared with landslides dating from March and October. Moreover, the corresponding absolute antecedent rainfall was also found to be above the 40-day period rainfall threshold. Here we characterize in detail the short and long-term atmospheric circulation conditions that were responsible for the intense rainfall episodes that have triggered the corresponding landslide events. It is shown that the three rainfall episodes correspond to considerably different synoptic atmospheric patterns, with the March episode being associated to an intense cut-off low system while the October and November episodes appear to be related to more typical Atlantic low pressure systems (and associated fronts) travelling eastwards. Finally, we analyse the role played by the North Atlantic Oscillation (NAO) during those months marked by landslide activity. It is shown that the NAO index was consistently negative (usually associated with above average precipitation) for the months prior to the landslide events, i.e. between October 2005 and March 2006, and again between August and October 2006. Article in Journal/Newspaper North Atlantic North Atlantic oscillation Directory of Open Access Journals: DOAJ Articles |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental technology. Sanitary engineering TD1-1066 Geography. Anthropology. Recreation G Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental technology. Sanitary engineering TD1-1066 Geography. Anthropology. Recreation G Environmental sciences GE1-350 Geology QE1-996.5 J. L. Zêzere R. M. Trigo M. Fragoso S. C. Oliveira R. A. C. Garcia Rainfall-triggered landslides in the Lisbon region over 2006 and relationships with the North Atlantic Oscillation |
topic_facet |
Environmental technology. Sanitary engineering TD1-1066 Geography. Anthropology. Recreation G Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Landslides occurred in the Lisbon area during the last 50 years were almost always induced by rainfall and have been used to establish rainfall thresholds for regional landslide activity. In 2006, three new rainfall-triggered landslide events occurred in the study area, namely on the 20 March, the 25–27 October, and the 28 November. Landslide events occurred in March and October 2006 include shallow translational slides and few debris flows, and the corresponding absolute antecedent rainfall was found to be above the threshold for durations ranging from 4 to 10 days. These events also fit the combined threshold of daily precipitation and 5 days calibrated antecedent rainfall values. Likewise the landslide event that took place in late November 2006 includes some slope movements with deeper slip surfaces, when compared with landslides dating from March and October. Moreover, the corresponding absolute antecedent rainfall was also found to be above the 40-day period rainfall threshold. Here we characterize in detail the short and long-term atmospheric circulation conditions that were responsible for the intense rainfall episodes that have triggered the corresponding landslide events. It is shown that the three rainfall episodes correspond to considerably different synoptic atmospheric patterns, with the March episode being associated to an intense cut-off low system while the October and November episodes appear to be related to more typical Atlantic low pressure systems (and associated fronts) travelling eastwards. Finally, we analyse the role played by the North Atlantic Oscillation (NAO) during those months marked by landslide activity. It is shown that the NAO index was consistently negative (usually associated with above average precipitation) for the months prior to the landslide events, i.e. between October 2005 and March 2006, and again between August and October 2006. |
format |
Article in Journal/Newspaper |
author |
J. L. Zêzere R. M. Trigo M. Fragoso S. C. Oliveira R. A. C. Garcia |
author_facet |
J. L. Zêzere R. M. Trigo M. Fragoso S. C. Oliveira R. A. C. Garcia |
author_sort |
J. L. Zêzere |
title |
Rainfall-triggered landslides in the Lisbon region over 2006 and relationships with the North Atlantic Oscillation |
title_short |
Rainfall-triggered landslides in the Lisbon region over 2006 and relationships with the North Atlantic Oscillation |
title_full |
Rainfall-triggered landslides in the Lisbon region over 2006 and relationships with the North Atlantic Oscillation |
title_fullStr |
Rainfall-triggered landslides in the Lisbon region over 2006 and relationships with the North Atlantic Oscillation |
title_full_unstemmed |
Rainfall-triggered landslides in the Lisbon region over 2006 and relationships with the North Atlantic Oscillation |
title_sort |
rainfall-triggered landslides in the lisbon region over 2006 and relationships with the north atlantic oscillation |
publisher |
Copernicus Publications |
publishDate |
2008 |
url |
https://doaj.org/article/72617509c2054765b3c3826f65454e4e |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_source |
Natural Hazards and Earth System Sciences, Vol 8, Iss 3, Pp 483-499 (2008) |
op_relation |
http://www.nat-hazards-earth-syst-sci.net/8/483/2008/nhess-8-483-2008.pdf https://doaj.org/toc/1561-8633 https://doaj.org/toc/1684-9981 1561-8633 1684-9981 https://doaj.org/article/72617509c2054765b3c3826f65454e4e |
_version_ |
1766130029322829824 |