LOUISA TSANG
PhD, Geophysics
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I am a geoscientist interested in understanding slip behaviour and tectonic processes along active fault zones using geodetic, geomorphological, and other geophysical data.
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I am currently a postdoctoral researcher at Géoazur working in the E-POST team. My work involves using GPS data to image the signature of early postseismic deformation following subduction zones earthquakes in South America. During my PhD at the Earth Observatory of Singapore, my thesis focused on understanding postseismic and long-term tectonic deformation along the Sumatran subduction zone, using long-duration GPS and coral (paleogeodetic) data. I am also interested in combining geophysical, geological and remote sensing data to map and understand tectonomorphic processes in active fault zones in Tibet.
NEWS
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July and September 2019: I will be visiting Imperial College London and University College London to give a seminar: Imaging afterslip along the Ecuadorian and Sumatran megathrusts over different timescales, using geodetic data
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April 2019: I will be visiting Coventry University and giving a seminar: Imaging the patchwork quilt of slip behaviour along subduction zones
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December 2018: I will be presenting the results of our study on early postseismic deformation following the 2016 Ecuador earthquake at the AGU 2018 Fall Meeting in Washington D.C.
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December 2018: I will be visiting Ifremer and giving a seminar: From Minutes to Centures: imaging earthquake cycle deformation along subduction zones using GPS and paleogeodetic data
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September 2018: I will be giving a talk at the 19th Assembly of Wegener in Grenoble, France.
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June 2018: I will be attending the 50 years of plate tectonics conference in Paris, France.
BRIEF CV
2017-PRESENT
POSTDOCTORAL RESEARCHER
Géoazur,
Centre National de la Recherche Scientifique (CNRS),
France.
Project: Imaging early postseismic deformation along subduction zones, using GPS data, and investigating frictional properties along megathrusts
2016
RESEARCH FELLOW
Earth Observatory of Singapore
Project: Imaging long-term postseismic deformation following large earthquakes along the Sumatran subduction zone
2011-2016
PHD CANDIDATE, GEOPHYSICS
Nanyang Technological University,Singapore
Earth Observatory of Singapore
Thesis title: Characterizing the spectrum of slip behaviour at the Sumatran subduction zone with long-term geodetic records
2009
VISITING RESEARCHER
International Seismological Centre
Berkshire, U.K.
2008
MSci GEOPHYSICS WITH A YEAR ABROAD
Imperial College London
University of California, Berkeley
2005
INTERN IN SEISMIC DATA PROCESSING
CGG Veritas
Crawley, West Sussex, U.K.
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PUBLICATIONS
Tsang, L.L.H., Vergnolle, M., Twardzik, C., Sladen, A., Nocquet, J.-M., Rolandone, R., Agurto-Detzel, H., Cavalié, O., Mothes, P. and P. Jarrin 2019. Imaging rapid early afterslip of the 2016 Pedernales earthquake, Ecuador, Earth and Planetary Science Letters, doi:10.1016/j.epsl.2019.115724.
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Tsang, L.L.H., Hill, E.M., Barbot, S., Qiu, Q., Feng, L., Hermawan, I., Banerjee, B. and D. Natawidjaja 2016. Afterslip following the 2007 Mw 8.4 Bengkulu earthquake in Sumatra loaded the 2010 Mw 7.8 Mentawai tsunami earthquake rupture zone, Journal of Geophysical Research, doi: 10.1002/2016JB013432.
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Tsang, L.L.H., Meltzner, A.J., Hill, E.M., Freymueller, J.T and K. Sieh 2015. A paleogeodetic record of variable interseismic rates and megathrust coupling at Simeulue Island, Sumatra, Geophysical Research Letters, doi:10.1002/2015GL066366.
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Tsang, L.L.H., Meltzner, A.J., Philibosian, B., Hill, E.M., Freymueller, J.T and K. Sieh 2015. A 15-year slow slip event on the Sunda megathrust offshore Sumatra, Geophysical Research Letters, doi:10.1002/GL064928.
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Tsang. L.L.H., Wurman, G. and R. Allen 2007. Magnitude scaling relations from P-waves in southern California, Geophysical Research Letters, doi:10.1029/2007GL031077.
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Lindsey. E.O., Almeida, R., Mallick, R., Hubbard, J., Bradley, K., Tsang, L., Liu, Y., Bürgmann, R. and E.M. Hill 2018, Structural control on down-dip locking extent of the Himalayan megathrust, Journal of Geophysical Research, doi:10.1029/2018JB015868.
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Morgan, P.M., Feng, L., Meltzner, A.J., Lindsey, E.O., Tsang, L.L.H. and E.M. Hill 2017. Sibling earthquakes generated within a persistent rupture barrier on the Sunda megathrust under Simeulue Island, Geophysical Research Letters, doi: 10.1002/2016GL071901.
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Meltzner, A.J., Sieh, K., Chiang, H.-W., Wu, C.-C., Tsang, L.L.H., Shen, C.-C., Hill, E.M., Suwargadi, B.W., Natawidjaja, D.H., Philibosian, B. and R.W. Briggs 2015. Similar seismic ruptures and interseismic strain rate variations on the Nias-Simeulue patch of the Sunda megathrust, Quaternary Science Reviews, 122, 258-281, doi:10.1016/j.quascirev.2015.06.003.
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Feng, L., Hill, E.M., Banerjee, P., Hermawan, I., Tsang, L.L.H., Natawidjaja, D.H., Suwargadi, B.W. and K. Sieh 2015. A unified GPS-based earthquake catalog for the Sumatran plate boundary between 2002 and 2013, Journal of Geophysical Research: Solid Earth, 120, 3566-3598, doi:10.1002/2014JB011661.
RESEARCH
EARTHQUAKE CYCLE DEFORMATION ALONG THE SUMATRAN SUBDUCTION ZONE
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PhD Advisor:
Emma Hill
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Main collaborators and thesis committee:
Aron Meltzner, Jeff Freymueller, Paul Tapponnier, Kerry Sieh, Lujia Feng, Qiu Qiang, Sylvain Barbot, Paul Morgan, Belle Philibosian, Eric Lindsey
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Along the Sumatran subduction zone, long-duration geodetic and paleogeodetic time series enable us to better understand the character of long-term (interseismic) and postseismic deformation along the megathrust. My PhD thesis involved answering the following questions:
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How does the seismic, postseismic and interseismic deformation history affect the timing and spatial pattern of seismic ruptures?
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Do slow slip events occur in the Sumatran subduction zone?
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From a record of interseismic deformation spanning multiple earthquake cycles, what is the character of interseismic deformation?
TECTONIC GEOMORPHOLOGY OF THE LUNGGAR RIFT, TIBET
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Collaborators:
Paul Tapponnier, Tai-Lin Tseng, Elise Kali, Marie Etchebes, Jonathan Aitchison
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Using a combination of satellite imagery, topographic data, seismicity data and moment tensor inversion techniques, we have produced tectonomorphic maps to understand the tectonically active landscape of the Lunggar rift in western Tibet.
EARLY POSTSEISMIC DEFORMATION FOLLOWING THE 2016 ECUADOR EARTHQUAKE
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Main collaborators:
Mathilde Vergnolle, Cedric Twardzik, Anthony Sladen, Jean-Mathieu Nocquet, Frédérique Rolandone
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High-Rate GPS observations following the 2016 Mw 7.8 earthquake offshore Ecuador enable us image the nucleation of afterslip in the initial hours after the earthquake, bringing us closer to the transition between the coseismic and postseismic phases of the earthquake cycle. My work addresses the following questions:
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How did early afterslip evolve in space and time?
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How much postseismic geodetic moment do we miss by not accounting for early afterslip?
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How does early afterslip relate to the mainshock rupture area, ensuing aftershocks, and longer-term afterslip?
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What are the frictional properties of aseismically slipping regions?
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VARIABILITY OF EARTHQUAKE RECURRENCE PARAMETERS IN THE AEGEAN, USING HISTORICAL AND INSTRUMENTAL CATALOGUES
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Advisor:
Saskia Goes
CALIBRATION OF THE ELARMS EARTHQUAKE EARLY WARNING SYSTEM IN SOUTHERN CALIFORNIA
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Collaborators:
Richard Allen, Gilead Wurman
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We develop empirical magnitude-scaling relationships from characteristics of the first 4 seconds of the P-wave arrivals. We incorporated these relationships into the ElarmS algorithms to evaluate the offline performance of the system.