Overview

Sources of geodetic information include tide gauges for measuring relative sea-level height, continuously operating Global Positioning System (GPS) receivers and Interferometric Synthetic Aperture Radar (InSAR) for measuring displacements of the Earth’s crust, and the GRACE satellite mission, which takes monthly snapshots of the Earth’s gravity field. These data sets together enable measurement of processes in the Earth system that include, amongst others, crustal deformation from tectonics and earthquakes, changes in sea level, volcanic deformation, melting glaciers, and changes in continental water storage.

With the advent of space-borne geodetic technologies, the quantity and spatial resolution of geodetic data have increased dramatically, and they continue to do so. Data precision has also increased dramatically, so we now need to understand not only the primary process affecting a measurement, but also many secondary processes that affect the measurements on a fine scale. For example, the gravity field at a single location can be affected by changes in nearby glaciers, hydrology, sea level, and tectonics, as well as measuring the ghosts of past ice sheets in the form of glacial isostatic adjustment.  

A focus of much of our research, therefore, is to combine multiple different geodetic data sets together to help separate the different signals in the data, and to provide better-constrained models for processes such as earthquakes and sea-level change. To place emphasis on the association of uncertainties with our results, we are investigating various techniques for Bayesian combination of data and models.

One of our primary data sets is the Sumatra GPS Array (SuGAr). This is a 48-station continuous GPS network maintained by EOS, designed to monitor tectonic deformation and earthquakes along the Sumatra subduction zone.  This network has recorded a huge number of large earthquakes over the last decade, and much of our recent work has focused on separating the effects of these different earthquakes in the time series, and studying their rupture histories. We are currently working on code to analyze the evolution of fault slip during the earthquakes, through inversion of high-rate (1-second sampling) GPS data.

Resources

Graphics

Map showing SuGAr stations, recent rupture patches on the Sunda megathrust, and volcanoes in Sumatra

Videos

Introduction to the Southeast Asia SEA-Level (SEA2) Program

Facilities

Sumatran GPS Array (SuGAr) 

Research Interests

Remote Sensing

Use remote-sensing data to:
• Support regional and local stakeholders and decision makers by monitoring and mapping regional hazards, environmental crises, and natural disasters
• Develop cutting-edge algorithms for hazards monitoring and disaster mapping (e.g., using machine learning techniques).

Projects

Myanmar-­India-­Bangladesh-Bhutan (MIBB) tectonic geodesy

The Myanmar-India-Bangladesh-Bhutan GPS network began operation in 2012 and now comprises 33 continu...
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A geodetic study of sinking cities and subsiding deltas in East and Southeast Asia

We are building a holistic understanding of regional sea-level change that includes influences from ...
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Sumatran Fault Monitoring (SuMo) Campaign GPS project

The Sunda megathrust has received a lot of attention in the last decade. However, information on the...
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Sumatran Tectonic Geodesy (SuGAr)

SuGAr has been observing surface deformation in Sumatra since 2002. The long time series are now a t...
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Selected Publications

Year 2021

Slip rate deficit and earthquake potential on shallow megathrusts

Eric O. Lindsey, Emma M. Hill, James D.P. Moore, Judith A. Hubbard, Kyle E. Bradley, Rafael V. Almeida, et al.

Year 2021

Long-lived shallow slow-slip events on the Sunda megathrust

Rishav Mallick, Aron J. Meltzner, Emma M. Hill, Eric O. Lindsey, Louisa L.H. Tsang, & Lujia Feng

The Team

CHIN Shi Tong

CHIN Shi Tong

Research Associate

Maybel D'SILVA

Maybel D'SILVA

Secretary

Emma HILL

Emma HILL

Principal Investigator

NG Shi Hui Grace

NG Shi Hui Grace

PhD Student

PENG Dongju

PENG Dongju

Senior Research Fellow

Mason PERRY

Mason PERRY

Research Fellow

Rino SALMAN

Rino SALMAN

Research Fellow

Jay WONG Cai Jie

Jay WONG Cai Jie

Project Officer

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