Nepal earthquake lowered Everest by up to 2.5 cm

Further analysis of the newly processed sentinel-1 satellite radar data shows that the area around the Kathmandu region was uplifted in the earthquake, while the area to the north of Kathmandu sunk (subsided).

The red region in the image below shows uplift while the faint blues to the north indicate subsidence. Mount Everest is located to the northeast of Kathamndu.

Processed Sentinel 1 results of the Nepal earthquake deformation. red = mostly subsidence, blue = mostly uplift.  Source: Pablo Gonzalez – LiCS/COMET+

Processed Sentinel-1 results of the Nepal earthquake deformation. red = mostly uplift, blue = mostly subsidence.
Source: Pablo GonzalezLiCS/COMET+

 

The image was produced by COMET researchers at the University of Leeds as part of the Look Inside the Continents from Space (LiCS) project led by CGS scientist Professor Tim Wright.

New computer modelling results estimate that the amount of lowering experienced in the Everest region could be up to 2.5cm. These numbers are very preliminary and will be verified over the coming days with further research.

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Clearer sentinel 1 image of Nepal earthquake deformation

A new clearer sentinel 1 satellite image has been produced by COMET researchers as part of the Look Inside the Continents from Space (LiCS) project led by CGS scientist Professor Tim Wright.

For Tim Wright’s preliminary interpretation of the results see our previous post.

Sentinel 1 image of the Nepal earthquake deformation. Source: John Elliot - LiCS/COMET

Sentinel 1 image of the Nepal earthquake deformation. 1 colour fringe = 10cm of ground deformation.
Source: John ElliotLiCS/COMET+

Monitoring earthquakes with radar satellites

From earthquakes and volcanoes to landslides and agriculture, radar satellites have revolutionised our ability to monitor the active processes changing the surface of the earth.

Radar satellite missions can measure millimetre-scale changes in Earth’s surface following an earthquake. On 24 August 2014, an earthquake struck California’s Napa Valley. By processing two images from the Sentinel-1A radar satellite, which were acquired on 7 August and 31 August 2014 over this wine-producing region, an ‘interferogram’ was generated showing ground deformation.

CGS researchers at the Leeds based Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET+) are at the forefront for using this technology to understand the active processes shaping the surface of the earth.

More information:
[1] http://www.esa.int/spaceinvideos/Videos/2015/02/Earthquake_monitoring_with_radar_satellites
[2] http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-1/Radar_vision_maps_Napa_Valley_earthquake
[3] http://www.see.leeds.ac.uk/research/igt/research-projects/looking-inside-the-continents-of-space/

National Earth Observation Centres move to Leeds

The Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET) and the Centre for Polar Observation and Modelling (CPOM) moved to the School of Earth and Environment, University of Leeds this month. The centres will receive over £5 million in core Natural Environment Research Council (NERC) funding over the next 5 years.

COMET, directed by CGS academic Prof. Tim Wright and including scientists from Leeds, Oxford, Cambridge, Reading, UCL, Bristol and Glasgow, exploits satellite data to model tectonic and volcanic processes.

CPOM, directed by Prof. Andy Shepherd and including scientists from Leeds, UCL, Bristol and Reading, measures changes to ice sheets and glaciers in order to study the impacts of climate change.

Both centres will analyse data from the recently launched European Space Agency Sentinel-1A satellite, which allows detection of millimetre-scale changes to the Earth’s surface.

Professor Tim Wright said: “Today’s changes mark a new chapter in the history of CPOM and COMET. It presents a golden opportunity for the scientific community to better exploit the growing volume of data collected by satellite sensors, placing the University of Leeds at the heart of the government’s strategy to drive economic growth through investment in space technologies.”

Ekbal

Read the detailed article on the CGS website by clicking here.

Workshop: Using Satellites to Map Earthquake Hazards

Earlier this year scientists from the University of Leeds met with international colleagues to advance global earthquake hazard mapping capabilities.

The University of Leeds recently held a focused international workshop on using satellite radar to map global earthquake hazard. Scientists and remote sensing experts from Europe, China, and America met to discuss how best to exploit data from the European Space Agency’s new Sentinel-1 satellite, which is due to be launched in early 2014.

Interferogram of the 2003 Bam earthquake.  (ESA)

Interferogram showing the surface deformation after the 2003 Bam earthquake.
(ESA)

In earthquake-prone regions, the ground slowly and steadily warps in the time period between earthquakes at a rate of a few millimetres to a few centimetres per year. This tectonic warping or strain can be measured using a satellite radar technique known as InSAR and can tell scientists which regions worldwide are most at risk from earthquakes in future.

This technique has been developed over the last decade, but the upcoming launch of Sentinel-1, a new InSAR satellite, presents a major opportunity to map and understand global earthquake hazard better than ever before.

The workshop focused broadly on two themes: assessing the current methods and techniques used to map tectonic strain with InSAR, and discussing the best ways to combine these data with complementary GPS measurements of the same deformation.

The keynote speech at the workshop was given by Corné Kreemer from the University of Nevada, the lead scientist on the Global Strain Rate Model (GSRM) project. This project currently uses only GPS measurements to produce a global map of tectonic strain, and is a major input into the Global Earthquake Model (GEM), an international public-private partnership which aims to produce comprehensive maps of seismic hazard. A major outcome from the meeting was the development of plans to integrate InSAR data into GSRM, which will not only improve spatial resolution of the strain model, but will also improve geographical coverage in remote areas where it is difficult to make GPS measurements.

GEM

The Global Earthquake Model

GSRM presents a good opportunity for InSAR data to feed into GEM, and to therefore make the results of research into InSAR strain maps available to a wide variety of users, both inside and outside the scientific community.

Another outcome from the workshop was the compilation of a feedback document for the European Space Agency to help shape the Sentinel-1 mission plan. This is hoped to ensure that the new satellite’s ability to map earthquake hazard is maximised. In addition, the attending scientists made plans for further international collaboration, including between industry and academia. A particular focus for the planned collaboration is the testing and comparison of different methods for InSAR data processing and strain mapping.

The Leeds workshop was hosted at the School of Earth and Environment and was funded by the School’s Climate and Geohazard Services (CGS). 22 experts attended the meeting from the UK, France, Spain, Italy, Germany, the Netherlands, China, and the US, representing not just academia, but also the remote sensing and space industries, and the European Space Agency.

Satellite Earth Observation: Understanding Natural Hazards

 

This is the first of two blogs on satellite Earth Observation. This article will focus on what can be achieved with this technology and the next will be on the strengths the University of Leeds’ School of Earth and Environment has in this field.

Recently I had the great opportunity to attend the European Space Agency (ESA)’s Living Planet Conference held this year in the historic city of Edinburgh. The conference brought together over 1900 people from all over the world with the common aim to share knowledge and expertise on how we use satellite earth observation data (particularly from European satellites) to better understand the world we live on.

In his talk at the plenary session ESA’s Director General Jean-Jacques Dordain pointed out that Earth Observation is by far the largest programme for ESA in terms of budget and that it is the scientists that fundamentally drive these missions.

Interfermoteric map of part of the Virunga Mountains, East Africa  (ESA). The colours can be used to determine the actively deforming regions.

Satellite radar map of part of the Virunga Mountains, East Africa. The colours can be used to determine the actively deforming regions.
(ESA)

Earth observer satellites play a pivotal role in providing data to better understand a multitude of 21st century societal challenges including but not limited to:

– Population growth and migration
– Food production and land use
– Energy
– Geohazards
– Climate change
– Weather, sea level and ocean currents
– Earth’s changing surface
– The Earth’s biomass
– The geomagnetic field and space weather

Rather than go into a lengthy discussion of all of these I will focus on how Earth observation has helped us to better understand geohazards and our climate.

The early satellites such as ERS-1 (1991), ERS-2 (1995) and ENVISAT (2002) paved the way for the satellite geodesy age. They’re almost two decades of constant monitoring of the Earth has provided a wealth of data for the scientific community which has been instrumental to improving our understanding of natural (and human induced) hazardous events. Even now, long after these satellites have been decommissioned, the archived data is used for ongoing research.

Synthetic interferogram for the 2003 Bam earthquake. The coloured fringes are essential contours of displacement during the earthquake. Source [1]

Synthetic interferogram for the 2003 Bam earthquake. The coloured fringes are essentially contours of displacement during the earthquake.
Source [1]

The extent of deformation from earthquake ruptures, for example, can often be misinterpreted from limited spatial data such as GPS and ground surveys. These satellites provided a means to determine the deformation from these events on large scales and at a high spatial resolution. Such studies led to the use of this data to measure the much smaller interseismic signals and the build-up of strain energy on locked faults. Even if these faults are not obvious in the landscape.

Parallel to this is the geodetic work to monitor active volcanoes. Satellite radar can be used to monitor to the uplift and subsidence of volcanoes which can be interpreted as inflation and deflation caused by the presence of magma. Such monitoring aided in providing early warning before the 2010 eruption of Mt Merapi in Indonesia and helped save thousands of lives.

The extent of floods and the potential for future flooding in a particular region can be assessed using space based geodetic monitoring. The location of landslides and the variation of surface motion can be monitored to determine the stability and likelihood that a landslide may be triggered by an incoming hurricane (which is also monitored using space based instruments).

Various gas concentrations (e.g. carbon-dioxide, sulphur dioxide, methane) in the atmosphere can be determined and their effects on the local and global climate studied. Such measurements are integral in adding boundary conditions to climate models which improve our estimates of the future effects of greenhouse gas emissions. Accurate weather reports rely on real-time satellite measurements of atmospheric pressure, humidity, temperature etc.

Sentinel-1, due to be launched early next year, will be the first dedicated Earth observation satellite for interferometry (i.e. mapping changes through time). Its long mission duration and systematic acquisitions will enable scientists to better understand the changing nature of the Earth’s surface through time. Such acquisitions will, for example, allow near-real time monitoring of volcanoes and and thus enable better and more accurate forecasting before these events. Also the detection of slow strain accumulation on large hazardous faults will be possible with only a few years worth of data.

Sentinel-1, due to be launched in march 2014. (ESA)

Sentinel-1, due to be launched in march 2014.
(ESA)

Four more Sentinel missions are planned for future years covering all the Earth observation topics such as biomass, sea level, atmospherics and land cover. ESA’s Open Access data policy also enables free access to all its mission data for both scientific and commercial use.

The next few years will certainly result in much greater efforts at understanding the workings of our little blue planet because after all, there is no alternative to planet Earth; we are here to stay.

Ekbal

 

More information:
    [1] Talebian et al., The 2003 Bam (Iran) earthquake: Rupture of a blind strike-slip fault, 2004, Geophysical Research Letters, vol. 31, L11611, doi:10.1029/2004GL020058
    [2] http://www.esa.int/Our_Activities/Observing_the_Earth