Application of satellite and airborne InSAR to volcano deformation

processes in the Pacific Rim

Paul Lundgren1, Pietro Milillo1,2, Alexey Kiryukhin3, Sergey Samsonov4, Fernando Gil5, Maria

Cordova5, Akiko Tanaka6, and Susan Owen1

1Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA, 2Scuola di Ingegneria, Università degli Studi della Basilicata, Potenza, Italy

3Institute of Volcanology & Seismology FEB RAS, Petropavlovsk-Kamchatsky, Russia 683006 4Canada Centre for Remote Sensing, Ottawa, ON K1A0Y7, Canada

5Observatorio Vulcanológico de los Andes del Sur, SERNAGEOMIN, Temuco, Chile 6Geological Survey of Japan, AIST, Tsukuba, Japan

Natural Resources Canada

Motivation • Volcano systems poorly understood: monitoring

relies on multiple in-situ and remote sensing data combined with improved physical models

• Geodesy, in particular InSAR, constrain volcano source location, volume, and geometry

We examine three Pacific Rim volcanoes with InSAR: – Tolbachik flank eruption (2012-2013) – Copahue (Argentina-Chile) on-going volcano crisis – Nevado del Ruiz (Colombia) deep inflation source

…showing limitations for each case

Tolbachik fissure eruption (2012-2013)

Fissure Eruption: started November 27, 2012 ended late August, 2013 Seismicity: started in May-June 2012, located SE of Plosky Tolbachik propagated into edifice and S

flank rift zone in the 2-3 days prior to the eruption

InSAR data: Descending: RADARSAT-2 2-year

interferogram COSMO-SkyMed 1-year interf. Ascending: COSMO-SkyMed 1-year interf. Lundgren et al., JVGR, in revision, 2015

Tolbachik interferograms

Quad-tree down-sampled interferograms using Lohman and Simons (2005) method

We first solve for a single tensile dislocation dike using a Bayesian, Markov-chain Monte Carlo approach

Okada tensile model parameter distribution

Boundary element elastic whole-space model with topography

Checkerboard test at different smoothing values shows the usual fall-off in resolution with depth, with reasonable resolution in the uppermost ~2-3 km

Finite dike model dip = 80°, Gamma=50

We choose a smoothing factor (Gamma) that balances data misfit and model opening roughness. Misfit is minimum for dip = 80°

Seismicity and dike location Finite fault model: dip = 80°, Gamma=50

Seismicity (courtesy of IVS) shows activity propagated from ESE of Tolbachik toward the summit. Fewer events occurred in relation to the dike, so correspondence of seismicity and dike model remain unclear.

Seismicity and dike location Finite fault model: dip = 80°, Gamma=50

Fewer events occurred in relation to the dike, so seismicity does not provide a detailed basis for comparison to dike model. Dike extending SW from the summit roughly conforms with seismicity magma moved through the edifice and into the rift zone. More stress change analysis needed to understand relationship with 1975-76 intrusion to the south.

Copahue Volcano, S. Andes First eruption late December, 2012

InSAR data: TS mean velocities and max LOS point TS

RSAT2

CSK

UAVSAR data

UAVSAR data

TS calculated using GIAnT

RSAT2

CSK

RSAT2 CSK

b

c

RADARSAT-2 data and interferograms courtesy S. Samsonov, Natural Resources Canada COSMO-SkyMed raw data through JPL/Caltech – CIDOT/ASI collaboration

Copahue Volcano, airborne UAVSAR (L-band, 20 km wide swath, 5 m pixel)

+

TS velocities & UAVSAR interferograms

CSK

RSAT2 CSK

UAVSAR UAVSAR

UAVSAR

TS calculated using GIAnT, UAVSAR processed by the UAVSAR Project, JPL

MCMC modeling: – Requires multiple sources – Yang source is too shallow relative to its radius of curvature need for numerically correct volume sources (i.e. using BEM or FEM models)

Nevado del Ruiz volcano, Colombia

5300 m Nevado del Ruiz, killed ~25000 people in November 1985, single greatest volcano death toll in past 100 years

Photo from: Ordóñez et al., EOS, 2015

Lundgren, P., S. Samsonov, C. Lopéz, and M. Ordóñez, GRL, submitted, 2015

InSAR data RSAT2 descending track 3-year time series linear rate

RSAT2 ascending track 3-year interferogram shown as linear rate

InSAR time series vs in-situ

Seismicity (gray), GPS vertical (blue), and eruptions (red) from Ordóñez et al. (2015) show inflation starting in ~February 2012, similar to the RSAT2 InSAR time series by S. Samsonov.

2010 2011 2012 2013

2011.5 2013 2015

LOS

disp

. (cm

) 0

10

0

4

8

Vert

ical

GPS

(cm

)

Model results for Mogi and Yang srcs

Yang produces slightly better gradient fits in both the near and far range

Markov Chain Monte Carlo solutions

F-test (F=71) for Yang source χ2 relative to Mogi, suggests Yang source is significant*, at the 99% level. * But does not account for correlated noise.

Mogi source scaled to same ∆P (17 MPa/yr) as the Yang spheroid

F test (F=71) for model improvement in χ2 improvement for Yang source relative to Mogi, suggests Yang source is justified*, and significant at 99% level. * But does not account for correlated noise.

Stress calculations for the spheroid chamber and an external compressive stress of 5 MPa Tensile |stress| (a, b) predict sill propagation from center, b-c axes plane (a). Compressive stress axes predict radial dikes would become sills. Possible explanation for location relative to Ruiz: lateral and upward migration (e.g. Rivalta et al., 2005) through sills and dikes.

Max |σ3| Dike/sill initiation

σ1 axes = dike prop. direction After Gudmundsson (2006)

Conclusions • We have shown several examples of volcano deformation where observations were

serendipitous and often lacking in temporal or geometric coverage. • Sentinel-1 will allow systematic studies from both ascending and descending tracks to

improve space-time constraints of volcano sources. • All available data sets, including higher spatiotemporal SAR data from satellites such as

COSMO-SkyMed and possibly UAVSAR are needed during volcano crises.

COSMO-SkyMed SAR data © 2013-2014 Agenzia Spaziale Italiana (ASI)

Adapted from Tilling (2008)

Copyright 2015. All rights reserved.