Current and potential use of high resolution imagery in volcanology

Transcription

1 Current and potential use of high resolution imagery in volcanology Marcello de Michele, Bureau de Recherches Géologiques et Minières (BRGM), Orleans, France With the contribution of: Jean Christophe Komorowski, Institut de Physique du Globe de Paris, France, UMR CNRS 7154 Patrick Allard, Institut de Physique du Globe de Paris, France, UMR CNRS 7154 Susanna Jenkins, Cambridge Architectural Research, Cambridge, UK Peter J. Baxter, Institute of Public Health, University of Cambridge, Cambridge, UK Franck Lavigne, Université Paris 1 Panthéon Sorbonne, Laboratoire de Géographie Physique, Meudon, France Fabrizia Buongiorno, Instituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy Christian Bignami, Instituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy Philippe Labazuy, Jean Luc Froger, Mathieu Gouhier, Sébastien Valade, Laboratoire Magmas et Volcans (LMV) et de l'observatoire de Physique du Globe de Clermont Ferrand, France. Pierre Briole, Ecole Normale Supérieure, Paris, France Thomas Walter, Volcano Tectonics group, Physics of the Earth dept., GFZ, Potsdam, Germany

2 Current and potential use of high resolution imagery in volcanology Motivation and needs: volcanic areas are often densely populated areas. We need to: prepare for the eruption, model/study the eruption, evaluate the impact of the eruption. 1) before the crisis - Hazard/risks assessment, hazard/risks potential - Elements at risk/vulnerability: need for mapping of infrastructures, buildings, land use, (other ) - geomorphology, geological structures, potential ground instabilities, vegetation cover (other ) - Digital Elevation Models (DEM) - monitoring of volcano edifice deformation High resolution data with very frequent acquisitions (e.g. once a months) 2) During the crisis - Dynamic of the eruption: mapping of lava flow, lahars, pyroclastic flows, plume evolution, quick damages assessment. - Emergency response (e.g. International Charter on Space and Major Disaster) -> help local authorities, planning civil protection intervention High resolution data with very frequent acquisitions (on a daily/hourly basis) 3) After the crisis - Damage assessments (surface changes detection) - Mapping the new topography (need of a new DEM) - Surface displacement measurements (source modeling); monitoring of volcano edifice deformation - High resolution data with very frequent acquisitions (on a daily/weekly basis)

3 Current and potential use of high resolution imagery in volcanology Contribution 01. The 2010 Merapi Eruption (Indonesia) Institut de Physique du Globe de Paris

4 SPOT5, (CNES ISIS) res. 2.5 m, Green Red NIR Gas and ash plume Ash fall 3 Pyroclastic surge 1 2 Pyroclastic flow Gendol valley High resolution (2.5 m) infrared composite image (SPOT5) of the area impacted by the centenial VEI 3-4 multistage eruption of Merapi (Indonesia) between 25 October and November Pyroclastic flows (light greay) and surges (dark grey) reaching 15 km and ash fall from the eruption caused widespread dammages to infrastructure (2000 buildings) and the environment, the activation a 20 km exclusion zone concerning potentially up to 1.5 million people, the safe evacuation of at least people for several weeks, and about 300 deaths.

5 WorldView 2, (Digital Globe) res. 0.5 m, IRC Flow lobe Site 1 Flow spillover Flow spillover surge surge Scoria flow Close-up view of deposits left by the passage on 5 November 2010 of numerous pyroclastic flows in the Gendol valley (thickness at least m). The very high-resolution and exceptional quality of the images allow to map individual flow lobes, distinguish flow types and flow from surge, identify flow indicators (trees), map in detail the distribution of deposits, understand flow emplacement dynamic, characterize and quantify remotely the building damage, map the area of maximum vegetation heat damage (healthy is red),.

6 WorldView 2, (Digital Globe) res. 0.5 m, IRC Site 2 Detail of geologic mapping different of pyroclastic flow deposits (pyroclastic turbulent surges, pyroclastic dense flows with valley confined and overspill facies) generated by different eruptive processes (dome collapse, vertical explosion column collapse) using very high-resolution image.

7 Site 2 Close-up Digital Globe WorldView 2 image (0.5m res) of the Merapi area on 11 November The 5 November distal dome-collapse pyroclastic flow and associated surge from (green outline) and eruption column collapse scoria-rich flow (yellow outline) are shown in the vicinity of Bronggang and Bakalan villages were at least 50 people died. Complete blockage of the Gendol river by these flow deposits (blue line) is causing a diversion of the Gendol river to the west and the formation of new channel by active lahars (blue arrows)

8 WorldView 2, (Digital Globe) res. 0.5 m, IRC Site 2 Bakalan Close-up view of the impact of multiple pyroclatsic flows on the village of Bakalan, about 12,8 km from the volcano. Pyroclastic flows from dome collapse have overspilled the main Gendol river channel and destroyed the village. Great detail of flow deposit morphology, flow type, and flow indicators can be seen on these images. Moreover the images allow high quality quantitative remote assessment of building damage given previous building vulnerability studies and ground prooth data which can be combined with casualty data.

9 WorldView 2, (Digital Globe) res. 0.5 m, IRC Site 2 A A Tree logs Bakalan Tree Building damage types can be remotely assessed (S. Jenkins). Large boulders from the pyroclastic flow have impacted the buildings and caused ignition of roof supporting structures with partial to total collapse.

10 Site 3 Close-up view showing trees that were felled by the passage of a turbulent pyroclastic surge (see deposit insert) on 5 November 2010 at about 7 km from the volcano. The image allows individual mapping of tree blow-down directions and thus a better understanding of flow dynamics and interaction with topography. Notice the different directions. Building damage typologies can be quantitatively assessed (S. Jenkins).

11 Site 3 Notice the different directions of tree log alignment as the flow interacted with deep ravines and several flow lobes joined in this area caused flow refocussing. Areas where building where shielded by topography can also be detected. These images provide key insights into how turbulent lethal pyroclastic surges interact at distance with buildings and what are the consequences on human survival (S. Jenkins, P. Baxter).

12 Current and potential use of high resolution imagery in volcanology Contribution 02. Etna Lava flow mapping INGV (Rome)

13 Etna Lava flow (comparison with groung truth) Lava Distribution map performed by means of the processor developed within ASI SRV (Sistema Rischio Vulcanico) project funded by Italian Space Agency. Two data sets have been used: QuickBird acquired on 27th May 2006; Terra Aster acquired on 8th August 2008

14 Current and potential use of high resolution imagery in volcanology Contribution 03. Multi scale topographic analysis of Socompa volcano (Chili) debris flow Laboratoire Magmas et Volcans, Observatoire de Physique du Globe de Clermont Ferrand (France)

15 : State of the art LABEX : 10 years ( ) programme (ANR, EU) Leader : Laboratoire Magmas et Volcans (UBP CNRS IRD, Clermont Ferrand) Focused on : Volcanic eruptions dynamics HAZARDS RISKS Lava FLOWS TOPOGRAPHY JC. Thouret A. Harris Ph. Labazuy ASH Plumes M. Gouhier K. Martelli JL. Froger DAMAGES DISPLACEMENTS + MeMoVolc : Measuring and modelling of volcano eruption dynamics (PI : LMV) European Science Fondation (ESF) Research Networking Programme,

16 Current and potential use of high resolution imagery in volcanology Socompa debris flow Socompa Objectives : - to constraint rheological parameters of numerical models - to study geomorphic structures 35 km 50 m 3 km Volume = 36 km 3 Age : 7500 years BP

17 Current and potential use of high resolution imagery in volcanology SPOT 5, stereo couple, panchromatic mode (resolution : 2.5 m) Date acquisition : 09/11/2006 DEM Spot 5 (10 m, 60x60 km) V. Alaux (TFE, 2010)

18 Current and potential use of high resolution imagery in volcanology Ikonos, 2 stereo couples, panchromatic mode (resolution : 1 m) 1 km DEM Ikonos (2 m, 14*14 km) V. Héritier (M2R, 2009) V. Alaux (2010)

19 Contribution 04. Stuctural analisys of Lazufre volcano (Andes) GFZ (Germany) University of Rome Tre (Italy) Ruch & Walter (2010)

20 Current and potential use of high resolution imagery in volcanology Contribution 05. Ground displacement measurements from airphotos & Active fissures enhancement by vegetation monitoring BRGM (France) IPGP (France)

21 Current and potential use of high resolution imagery in volcanology Surface displacement of Piton de la Fournaise volcano retrieved from correlation of airphotos ( ) de Michele & Briole (2007) Digital image correlation Offset measurements

22 Current and potential use of high resolution imagery in volcanology Active fissures enhancement by vegetation monitoring and Nyiragongo On Etna volcano Houlie et al. (2006)

23 Current and potential use of high resolution imagery in volcanology Conclusions : potential of HR data for the volcano community? High resolution (HR) satellite Images allow to map and study a large number of phenomena related to volcanic hazards and volcanic risks. But : at present time HR data are often too expensive and not easily accessible for both the scientific community and for the humanitarian community. Moreover, HR data are not systematically acquired over volcanic areas therefore it is often a change to be able to get the right data at the right moment. The community claims for a platform dedicated to study/monitor natural hazards and associated risks (like the Space Volcanoes Observatory SVO- mission). We hope that PLEIADES could fulfill these needs! Potential of frequent repeat cycle + high resolution: dynamics of fast moving ground displacements Potential of multispectral capability + high resolution: coupling between eruptive activity and biophysical parameters Potential of frequent repeat cycle + high spatial resolution: strain measurements Potential of frequent repeat cycle : dynamic of the eruption (lava flow velocity fields, plume evolution, ) Stereo acquisitions: high resolution DEM extraction, vulnerability assessment, Acknowledgements : thanks to all the contributors! Financement des images (IPGP): Images Digital Globe acquises par l IPGP via le projet «CASAVA», coordinateur JC Komorowski, programme RISKNAT financé par l Agence Nationale de la Recherche (ANR) Images SPOT5 acquises l IPGP via le programme «ISIS»(CNES INSU IGN SPOT Image)

24 Nabro volcano (Eritrea, June 2011) from ALI Advanced land Imager onboard EO 1