Fernanda Ledo G. Ramos (1) Fernando P. De Miranda (2) Federal University of Rio de Janeiro UFRJ/COPPE

Transcription

1 USE OF INFORMATION DERIVED FROM RADAR REMOTE SENSING (RADARSAT-1 INTERFEROMETRY AND SRTM MOSAIC) FOR MAPPING NEOTECTONIC ACTIVITIES IN THE REGION OF MANAUS (AMAZONAS STATE) Fernanda Ledo G. Ramos (1) Fernando P. De Miranda (2) (1) Federal University of Rio de Janeiro UFRJ/COPPE (2) PETROBRAS Research and Development Center - CENPES

2 Objective Understand and contextualize, from a tectonic and structural standpoint, the results obtained by an interferometric study recently carried out in the Manaus area, Amazonas State, in which a stack of archived RADARSAT-1 data has been processed by MacDonald Detwiller and Associates (MDA). These preliminary results are part of the ongoing Solimões Neo-Tectonic InSAR Project developed by Petrobras. Research Question The research question has been approached through the analysis of the drainage network extracted with the aid of SRTM (Shuttle Radar Topography Mission) data, as well as through the comparison with images from different optical sensors and with geologic/geomorphologic information available in the literature.

3 Area of Interest Manaus is the biggest city in the Brazilian Amazonia Terrain elevation ranging m

4 Methodology Overview Problem Bibliography research DEM SRTM Processing Landsat e IKONOS Data Processing. Statistical and structural analysis from geologic and geomorphologic available data Compilation of results from InSAR RADARSAT-1. Integration GIS Analysis of geologic implications Conclusions and recommendations

5 InSar - Atmospheric Effects Atmospheric effects over the same areas for Los Angeles and Manaus, both from RADARSAT-1 stacks (MDA, 2008)

6 Interferograms RADARSAT-1 28 scenes RADARSAT-1 Beam Mode Fine 2 F (8 m / 50x50km) From August 2006 to December _ _ _ _ _ _ _ _ _ _ _ _

7 Preliminary Results from InSAR _ _ Area of Crustal Movement (ACM) _ _ _ Petrobras (2008) Drainage Circular anomaly 4 km

8 SRTM Data Processing and Analysis Manaus Amazonas River

9 SRTM Data Processing and Analysis Geomorphic Index - Drainage Basin Tilting Tilt Numeric Example Basin tited to the left (looking downriver (from Salamuni et al., 2004; Keller and Pinter, 1996; Hare & Gardner 1985). Af = Asymmetric factor measures river changes associated to tectonics.

10 Results Tilting direction and tectonic effect values based on Af index. Tilt Tilt Existence Direction Tectonic effect Drainage Basin Ar (km²) At (km²) Af Igarapé Tarumã -Açu Yes Right pretty Rio Cuieiras Yes Right pretty Igarapé Tarumã -Mirim Yes Left medium Rio Preto da Eva Yes Right little Rio Puraquequara Yes Right little Igarapé Jatuarana No N/A little Igarapé Sao Raimundo Yes Left pretty Igarapé Educandos Yes Left medium Igarapé da Colônia No N/A little ( adapted from Salamuni et al., 2004). Different Tilting orientation in the north and south regions. AMC is located in the middle. ACM

11 Results Watersheds Stability based on tectonic magnitude calculated by Af index Unstable Watershed Moderated Unstable Watershed Little Unstable Watershed Moderated Stable Watershed Stable Watershed Area of Interest Flooded area Waterbody ACM Big tectonization process Medium tectonization process Poor tectonization process

12 Results The red basins are the most tectonized ones, and the red lines represents the unstable watershed topologic relationship. The ACM (Area of Crustal Movement) is located in the unstable limit. ACM

13 Results Slope from SRTM data enhances the circular drainage anomaly Circular drainage ACM Curvilinear Topographic Picks

14 Results Detailed information about the ACM - IKONOS Cidade Nova ngh.

15 Results and Conclusions Geologic and geomorphologic control on ACM.

16 Conclusions The Area of Crustal Movement (ACM) detected by the interferometric study is located above the tectonic unstable watershed that separates the Igarapé São Raimundo and Rio Tarumã-Açu sub-basins. Both areas are characterized by the pronounced occurrence of tilting. In addition, the ACM is situated in the vicinities of a circular drainage anomaly with 4 km of diameter, which strongly suggests a geologic origin for the interferometric feature. The severe atmospheric effect over the study area precludes any definitive results at this time. The continuing data (RSAT-2) acquisition and processing should improve this study.

17 Special Thanks for MDA Bernhard Rabus and Bruce MacDonald Federal University of Manaus UFAM 3vGeomatics Adrian McCardle Petrobras CENPES and Threetek for financial support