Glacial Hazard MonitoringWith Seismology

Fabian Walter2009 – Dr. sc. ETH Zürich2004 – MSc University of Colorado, USA2002 – BSc Brigham Young University, USA

Host: Laboratory of Hydraulics, Hydrology and Glaciology VAWETH Zürich

(at work)

Can we predictdestructiveglacier failure?

Raymond et al. (2003)

Allalingletscher, VS (1965)Unteraargletscher, BE

Weisshorn (4505 m), VS

“Hanging Glaciers”Frozen to bed

Steep glacier tongue• Sliding bed• Subglacial hydraulics

Raymond et al. (2003)

Gornersee,VS

Rock Glacier

Ice dam failure

1.2 km

Early Warning

Monitoring limitationsSurface targeted, only

“See” into the glacier• Fracture state• Basal drainage Seismic noise

measured in situ

Hanging Glaciers: Natural Frequency

Stiffness K• Material quality• Structural damage• Monitoring

collegevibe.com

Milikan Library, California

Chamousset Rock Column, France(Levy et al., 2010; Bottelin et al., 2013)

Hanging Glaciers Break-off• Resonance peak monitoring• Early warning sign• Volume estimate

Resonance Peaks• Frequency decay

prior to failure• Flexure mode

Directional Fourier Transform

Frequency (Hz)

Monitoring of Ice Dam Fractures Rock Glacier

Fracture state seismic velocities

Seismic noise monitoring• “Virtual hammer blows”:

No hammer needed!• Idea: ice dam monitoringHammer blow Force impulse

Seismic Noise Interferometry

Cross-correlation

Walter et al., subm

itted to G

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Steep Glacier Tongues: Seismic Water Tremor

Roger Braithwaite, U Manchester

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Matched filter processing

Source: USGS

Can Distant Earthquakes TriggerGlacier Failure?

Triggered Glacier Failure?• 2005 Weisshorn break-off only three

days after 9th largest earthquake since 1990 (M8.6 in Indonesia)

• Induced crevasse opening in Antarctica (Peng et al. (2014) in ngeo)

• Glaciers at tipping point?

Landslide in Alaska Range afterM7.9 2002 Denali Fault earthquake

Search digital seismic records for earthquake-induced fractures

Digital seismic records at host institute

Implementation

23 cm

Geopebble (Penn State)

FREEW

IRELESS

Instrument installation• Hanging glacier• Steep glacier tongue• Ice dam

80 cm

Conventional glacier installation

Implementation

2 PhD Students Enough data, fieldwork, subprojects for master’s students

…

1 field engineerTasks1. Tool translation to glaciers2. Data analysis3. Instrument installation

Host Institute: Laboratory of Hydraulics, Hydrology and Glaciology VAW

(ETH Zurich)

Seismology

Glaciology Natural

Hazards

Seismic Noise• U Grenoble• UC San Diego• Stanford• USGS

VAW• Since 1970’s• Field experience

Earthquake Triggering• UC San Diego• Georgia Tech

Fieldwork, instruments• U Grenoble• Penn State

ETH-Internal Collaboration• Swiss Seismological Service• Geophysical Institute

Career Goal: Faculty Position

Teaching: Physics of GlaciersGlaciology Natu

ral

Hazards

Seismology

Fieldwork

Stability

Hydraulics

DamageMechanics

GPS

Photogrammetry

Radarinterferometry

Early warningsystems

Engineeringseismology

Noise interferometry

SensorinstallationFinite element

modeling Data handling

Thank you foryour attention!

Weisshorn: Continuous Spectrograms

Glacier Seismology

Glacier Seismology

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Career Outlook in Switzerland

GLACIER SEISMOLOGYNATURAL HAZARDS

ETH Zurich:Assistant professor in engineering glaciology

Seismic detection of debris flow/landslide/snow avalanche detection and early warningSwiss Federal Institute for Forest, Snow and Landscape Research WSL:

SLF Uni Berne: Institute of Geological Sciences

Lausanne: Institut de Géographie et Durabilité

Steep Glacier Tongues: “Active” Phases

Röthlisberger and Kasser (1978)

Efficient subglacialdrainage: Melt-suppressed sliding

Inefficient subglacialdrainage: Melt-enhanced sliding

Digital Seismic Records at ETH (since 1997)

Alpine Glacier Seismology• Collaboration VAW- Swiss Seismological Service• Altogether over 3 years of continuous

seismic records

Can Earthquakes Cause Glacier Failure?

Peng et al. (2014)Nature Geoscience

Dynamic FracturingSearch glacier seismic records for earthquake-triggered icequakes

Crevassing events triggered by earthquake surface waves