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TitleDeformations occurring in the city of Auckland, New Zealand as mapped by Differential Synthetic Aperture Radar
AuthorSamsonov, SORCID logo; Tiampo, K; Manville, V; Jolly, G
SourceSecond workshop on USE of Remote Sensing Techniques (USEReST) for Monitoring Volcanoes and Seismogenic Areas; by USEReST 2008; 2008, 4 pages,
MeetingMt Ruapehu is New Zealand¿s most active volcano. In 2007, the volcano produced a large lahar following a crater lake dam wall breach, in addition to a minor eruption and small associated lahars. Here, satellite remote sensing and image processing is used to extract the path of the major lahar, and to compare the results achieved through classification of ASTER visible and near infra-red imagery to those derived from ALOS-PALSAR L-band synthetic aperture RADAR data. This study also details how remote sensing can be used to derive temperature values useful for monitoring volcanic activity. Eleven ASTER thermal images were acquired to extract the temperature of the crater lake and a linear correlation coefficient (r2) of 0.94 was achieved when compared to field survey. The results herein demonstrate the utility of satellite remote sensing for mapping and monitoring volcanic activity in New Zealand.; Naples; IT; November 11-14, 2008
Mediadigital; on-line; paper
File formatpdf
AreaAuckland; New Zealand
Subjectsgeophysics; remote sensing; deformation
AbstractAuckland is the largest city in New Zealand with a current population of more than one million. It is situated on a basaltic volcanic field with a total area of 360 square km and which consists of over 50 individual largely monogenetic volcanoes. The most recent and largest eruption occurred 600 years ago, and was witnessed by local inhabitants. It is anticipated that the chance of reawakening of a dormant volcano is very low; however, a new volcano could be created at any time in a new location within the field. In order to study ground deformations in the Auckland region twenty six ENVISAT ASAR images (Track 151, Frame 6442, IS2, VV) were acquired, spanning the period from 18 July 2003 to 9 November 2007. Over a hundred differential interferograms with perpendicular baselines of less than 500 meters were calculated and analyzed. Stacking, Small Baseline Subset and Permanent Scatterers processing algorithms were used to determine spatial and temporal patterns of surface deformation as well as average rates. A number of localized deformation regions were consistently observed by all three techniques. Three regions of subsidence are believed to be caused by groundwater extraction. The nature of uplifts is currently unclear, but a linear feature paralleling the regional tectonic fabric may be related to a hidden fault. The observed temporal deformation pattern is noisy but appears to be close to linear.

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