Characterization of hazards in the Andes and the Philippines using InSAR time seriesAnieri Morales Rivera1, Falk Amelung1, Patricia Mothes2, and Rodrigo Eco3

1Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL2Instituto Geofisico, Escuela Politecnica Nacional, Quito, EC

3National Institute of Geological Sciences, University of the Philippines, Metro Manila, PH

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76° 78° 80°

4°

2°

0°

2°

0 100 200 30050

Galeras

GuaguaPichincha Reventador

Tungurahua

Sangay

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p

70° 72° 74°

14°

16°

18°

-¯0 100 200 30050

km

0 875 1,750 2,625437.5Kilometers

¯

Legend

Country Boundary

- -

- --

-

-

-

-

Ecuador

Colombia

Peru

Legendp Deforming Volcanoes

Holocene VolcanoesCities

B

AA

B

Chile

CerroAuquihuato

Guayaquil

Cali

Quito

Arequipa

-3 -2 -1 0 1 2 3

LOS Velocity (cm/yr)Bogota

What is InSAR? Interferometric Synthetic Aperture Radar (InSAR) is a radar technique used in geodesy and remote sensing. InSAR satellites measure wave phase changes in the line-of-sight (LOS) between two different acquisitions that can show subtle to abrupt ground displacement.

The capabilities of satellite-based Interferometric Synthetic Aperture Radar to measure ground deformation at regional scales are well known but applied infrequently.

~2πϕ1

ϕ2

~2πϕ1

ϕ2

0 π 2π

Tungurahua volcano: ALOS Ascending 26/12/2007 – 27/03/2008

LOS

2 km

wave phase cycle

Satellite Flight

Direction

(Ascending)

Product Example (converted to surface displacement)

-11.8 11.80

Subsidence/East

Uplift/West

LOS change (cm)

InSAR applications in the PETROLEUM INDUSTRY include reservoir monitoring, salt diapir intrusion monitoring, CO2 storage monitoring, pipeline monitoring, storage site monitoring, structural mapping, among many others.

Data and Methodology

-8

-6

-4

-2

0

2

4

-30

-25

-20

-15

-10

-5

0

5

2007 2008 2009 2010 2011

0 3 6 91.5Kilometers

# Holocene Volcanoes

Cities

galeras_contr

auquihuato_contr

sangay_contr

tungurahua_contr

reventador_contr

Trench

Country Boundary

-77.36° -77.28°

1.24°1.16°

77.6° W77.64° W77.68° W77.72° W

0.04

° S

0.08

° S

0.12

° S

0 3 6 91.5Kilometers ¯

Legend#* Deforming Volcanoes

# Holocene Volcanoes

Cities

reventador_contr

Trench

Country Boundary

-77.68° -77.60°

-0.04°-0.12°

LO

S di

spla

cem

ent

(cm

)

Time (years)

-6.3 ± 0.8 cm/yr

-0.8 ± 0.5 cm/yr

3 km

3 km

2600 m

2800 m

2000 m

2400 m

d

ba

c

-3 -2 -1 0 1 2 3

LOS Velocity (cm/yr)

-2

0

2

4

6

8

10

-1.55°-1.45°L

OS

disp

lace

men

t (c

m)

Time (years)

0 1 2 30.5Kilometers ¯

Legend#* Deforming Volcanoes

# Holocene Volcanoes

Cities

pichincha_contr

tungurahua_contr

reventador_contr

Trench

Country Boundary

0 3 6 91.5Kilometers ¯

Legend#* Deforming Volcanoes

# Holocene Volcanoes

Cities

tungurahua_contr

reventador_contr

Trench

Country Boundary

-78.45°-78.55°

-0.20°-0.16°

-78.60°-78.64°

3 km

3 km

2.6 ± 0.5 cm/yr

-1.2 ± 1.4 cm/yr

4400 m

3800 m

2400 m

3600 m

a b

d

-3 -2 -1 0 1 2 3

LOS Velocity (cm/yr)

-2

0

2

4

6

8

10

0

6

12

18

24

30

2007 2008 2009 2010 2011

c

1.7 ± 0.6

25.5 ± 1.8 cm/yr

cm/yr

cm/yr5.4 ± 1.1

5.7 ± 0.7 cm/yr

1.1 ± 0.6 cm/yr

78.3° W78.33° W78.36° W78.39° W

1.95

° S

1.98

° S

2.01

° S

2.04

° S

0 3 6 91.5Kilometers¯Legend

#* Deforming Volcanoes

# Holocene Volcanoes

Cities

sangay_contr

tungurahua_contr

reventador_contr

Trench

Country Boundary

LO

S di

spla

cem

ent

(cm

)

Time (years)

-2.04°-1.98°

-78.36° -78.30°

3 km

3000

m

3600 m

-20

-14

-8

-2

4

10

0

3

6

9

12

15

2007 2008 2009 2010 2011 0

5

10

15

2007 2008 2009 2010 2011

73.14° W73.16° W73.18° W73.2° W

15.1

2° S

15.1

4° S

15.1

6° S

0 1 2 30.5Kilometers

¯Legend# Holocene Volcanoes

Cities

galeras_contr

auquihuato_contr

sangay_contr

tungurahua_contr

reventador_contr

Trench

Country Boundary

1.8 ± 0.3 cm/yr

LO

S di

spla

cem

ent

(cm

)

Time (years)

-73.18° -73.14°

-15.12°-15.16°

3 km

3800 m4000 m

1.8 ± 0.3 cm/yr

1.3 ± 0.4 cm/yr

-4.3 ± 0.4 cm/yr

-3 -2 -1 0 1 2 3

LOS Velocity (cm/yr)

a b

c d

4 km 4 km 4 km 4 km

LOS LOS LOS LOS

Galeras Guagua Pichincha Tungurahua Cerro Auquihuato

Obs

erva

tion

Mod

el

Res

idua

l

a b c d

e f g h

i j k l

LOS displacement (m)

-0.07-0.05-0.10-0.08

0.070.050.100.06

GalerasGuagua PichinchaTungurahuaCerro Auquihuato

0000

!

What are the Objectives?

1) Identify and monitor time-dependent deformation over volcanoes active during the Holocene at regional scales. 2) Characterize magmatic pressure sources in the subsurface through geo-physical inverse modeling.

3) Detect and characterize deformation signals unrelated to volcanoes, and identify the source.

4) Evaluate the potential hazards within the study regions.

Import data from ASF

Generate SLC images with GAMMA

Process InSAR with ROI_PAC

SBAS network selection

Invert for time series

Check unwrapping, remove dates with ionosphere

Correct for errors (unwrapping, DEM, planes, and troposphere)

Noise correction from ref-erence pixel near interest

point

● ALOS 2006-2011 ascending data from JAXA were ob-tained through the Alaska Satellite Facility (ASF). ● We select interferograms with perpendicular base-lines of less than 2,000 meters, temporal baselines of less than 2 years, and temporal baselines of 34 to 38 and 46 to 50 months.

● Interferograms were phase-unwrapped and inverted for the phase with respect to the first acquisition.

● Our time series was performed using the Small Base-line Subset method (SBAS) (maximum spatial baseline of 2 km) and processed with the PySAR software (Fattahi, 2015).

● Temporal coherence of each pixel was computed to select pixels above the 0.7 threshold.

Unwrapping

Before After

Ionosphere

Interferogram Time series – No corrections

After DEM error correction

After plane removal

After mask with 0.7 threshold Other errors

Study Area 1: Volcanoes of the Northernmost Andes

0 0.2 0.4 0.6 0.8 10

0.2

0.4

0.6

0.8

1

3 2 1 0 1 2 3Average LOS Velocity (cm/yr)

10 km

LOS

5.7 cm/yr

1.2 cm/yr

3.0 cm/yr 1.7 cm/yr

3.0 cm/yr

???

Envisat Descending 2003-2006

0 0.2 0.4 0.6 0.8 10

0.5

1

4 3 2 1 0 1 2

Average LOS Velocity (cm/yr)

Above: Averaged 2006-2011 LOS velocity map constructed with ALOS InSAR data. Velocity colormap: Blue = movement away from statellite. Red = move-ment torwards the satellite.

Observed Deformation and Source Modeling

Div. of Marine Geology and Geophysics4600 Rickenbacker CswyMiami, FL 33149

amorales@rsmas.miami.edu

Galera

s

Reven

tador

Guagua P

ichin

cha

Tungura

hua

Sanga

y

7 km S

E Cer

ro

Auquih

uato

!

Volcano Source Deptha (km)

Length (km)

Width (km)

Opening (m)

Strike (°)

Dip (°)

Magnitudeb

08/05/2007-09/28/2010 LOS displacement; rms = 18.27 mm Galeras Okada -1.61

1.76

3.78 -0.17 0.01

37.00 -1.20*106

12/23/2006-08/15/2009 LOS displacement; rms = 9.72 mm Guagua Pichincha

Mogi 1.82

0.12

12/23/2006-06/30/2009 LOS displacement; rms = 16.82 mm Tungurahua

Yang (Shallow Source)

2.40

2.78 1.08

87.00 35.70 0.08

Okada

(Deeper Source)

0.04

0.30

7.65 0.79 307.70

-21.92

1.80*106

01/16/2007-01/27/2011 LOS displacement; rms = 6.87 mm

SE of Cerro Auquihuato

Okada 2.83

1.28

1.39 0.10 198.86

-10.22

0.20*106

aDepths are expressed with respect to sea level (positive and negative values are respectively above and below sea level). bMagnitudes are expressed as volume change (m3) for Okada and Mogi sources, and as pressure change (10-5 µPa) for Yang sources.

Volcano Galeras Reventador Guagua Pichincha

Tungurahua Sangay Cerro Auquihuato

Deformation Source

Subsidence due to magma chamber depressurization

Subsidence of lava and pyroclastic flows

Inflation due to hydrothermal or magmatic pressure source

Inflation due to magma chamber pressurization

Downslope movement due to flank instability

Inflation due to hydrothermal or magmatic pressure source

Supporting Evidence

Seismic, magnetic, and gravity data

Geodetic data and field observations

Seismic data and field observations

Field observations, petrological, seismic

N/A

N/A

Study Area 2: Manila Region, Philippines

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#V

#V

#V

#V

Taal

MayonBulusan

Kanlaon

Manila

124°0'0"E120°0'0"E

18°0'0"N

14°0'0"N

10°0'0"N

6°0'0"N

¯0 200100Kilometers

Implications for Hazard Assessment

1) Volcanic hazards ● Deformation during magmatic eruptions measured only for volcanoes with shallow sources (Galeras and Tungurahua), in-dicating higher eruption risk due to proximity of magma to the surface. ● Only at Tungurahua we observed long term inflation due to magma ascending and reaching the surface, indicating success for monitoring eruption hazards with InSAR. ● Inflation at Cerro Auquihuato and Guagua Pichincha vol-canoes suggests volcanic unrest during the analysis period attrib-uted to pressurization of shallow sources, indicating the possibil-ity of an impending eruption in the near future. ● Flank instability at Sangay is a hazard to local popula-tions due to the possibility of a future flank collapse which could also trigger an eruption.

2) Subsidence hazards ● Subsidence due to groundwater extraction is a wide-spread problem and immediate actions should be taken. ● Fastest subsidence rates are occurring in the capital of Philippines (Manila), a region particularly vulnerable to flooding. A continuation of these rates will cause further damage to build-ings and infrastructures and will lead to future increase in fre-quency and spatial extent of flooding. ● Motion of some faults within the region could partly be driven by water extraction.

3) Faulting hazards ● Movement of faults that were previously mapped (Marikina Fault System) and a possible unmapped fault should be studied in detail to estimate the expected earthquake magnitudes and associated hazards.

Flooding in Manila ©NBC News

Subsidence Maps: Excessive Ground Water Withdrawal

Manila and Surroundings

Bacoor, San Pedro, and Dasmariñas Cities

Makban Geothermal Power Complex

(Top ten biggest geothermal plants in the world!)

Above: Damage to infra-structure in Manila related to displacements of the Marikina Fault system.Left: Main tectonic struc-tures in Central Luzon, Phil-ippines for reference.

Makban Power Plant Pipelines

Structural Maps: Faults

Left: Averaged 2006-2011 LOS velocity map constructed with ALOS InSAR data (Plotted over Google Earth). Colored rectangles are subsets of the figures below.

Final velocity maps

LOSSatellite

OrbitLeft: LOS displacement time series and velocity maps for each deforming volcano.Below: Sources of observed deformation supported by multidisciplinary evidence.

Figure and table above: Best fitting soultions for magmatic sources em-bedded in a homogeneous elastic half-space with topographic aproxima-tion

Below: InSAR LOS velocity maps from Envisat De-scending (left) and ALOS Ascending (right) data for the given time periods. Black lines = previously mapped faults from Marikina Fault system. Red dashed line = possible unmapped fault. Various faults can be identified but are not labeled in the figure for visualization pur-poses.

22-23 September 2015George R. Brown Convention CenterHouston, Texas

18th Annual

ALOS Ascending 2007-2011

???

LOS

Laguna de Bay (Caldera)

Manila Bay

© Rimando, R.E., Knuepfer, P.L.K. (2006)

Above: Averaged 2006-2011 LOS velocity map over Manila region within the Philip-pines. Deformation results are available for labeled volcanoes (e.g. Morales et al., 2015)

Left and Above: Overpopulated Manila is sinking and flooding fast!