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IMPLEMENTING GEOSS

GEO Supersites speed access to space data on Haiti earthquake

A new web portal for the “Haiti Supersite” was established last month as an impressively rapid response to the devastating earthquake that struck Port au Prince on 12 January. This marks the first time that satellite agencies have provided data – and provided them quickly – to a central data repository accessible by researchers. As a result, researchers were able to generate early analyses of aftershock hazards and information products of benefit to both scientists and operational users.

The Geohazard Supersites and their associated web portals were initiated last year by the geohazard scientific community as a contribution to GEO. There are currently three volcano Supersites – Mt. Etna, Vesuvius/Campi Phlegreii and Hawaii – and four earthquake Supersites – Istanbul, Tokyo, Vancouver/Seattle and Los Angeles. “Event Supersites” have been established for the 2009 L’Aquila earthquake and, most recently, for Haiti.

The Supersites feature raw synthetic-aperture radar (SAR) data as well as Global Positioning System (GPS) and seismic data. The aim is to ensure easy access to Earth science data in order to promote their use and to advance scientific research, ultimately helping to reduce the loss of life from natural hazards.

The Haiti Supersite’s portal also facilitates the exchange of data products such as seismic maps, damage maps, topography data, visible and infrared images, interferograms, and useful links.

A new paradigm

Until recently, geohazards researchers have had to order each satellite image and data set individually, leading to lengthy delays. Thanks to a web server established by the European Space Agency, space agencies and other data providers can now post their geological and seismographic images and data one time only for widespread use. This allows researchers to assess the cause of the earthquake and the risk of aftershocks in a timely manner.

In the case of Haiti, the Supersites initiative proved itself on 26 January when JAXA posted essential images taken on the previous day. By comparing these images with pre-quake images, researchers were able to develop interferograms (see below) revealing the details of ground deformation. When combined with other data and products, this allowed researchers to make the best and most rapid estimate yet of the risk of another earthquake. The top priority for the scientific community is to understand the previous earthquake and to feed this information into seismic risk estimations.

 

Interferogram of Haiti's earthquake

 

Operational users

While researchers are applauding this improved access to raw satellite data, a key next step for the Supersites is to reach out to operational users. Falk Amelung, a researcher at the University of Miami and Task Leader of the GEO Supersites initiative, believes research coming our of the Haiti Supersite data could be useful to planners responsible for rebuilding Port au Prince.

For example, as revealed by the interferogram, only 46 km (the red line) of the segment that ruptured in 1751 moved during the January earthquake. This suggests that the likelihood of another major event close to Port au Prince in the next few decades is high. Based on this information, planners may want to rebuild destroyed government buildings and public infrastructure such as hospitals further north, away from the fault line and the region of thickest sedimentary fill in Port au Prince’s alluvial valley. This is in turn could affect the patterns of private development, leading to less destruction should there be another earthquake.

Another approach that may be worth exploring is to link the outputs of the Supersites to the International Charter on Space and Major Disasters, which is already geared to supporting civil protection, rescue workers and other operational users.

Building on success

The effectiveness of the GEO Geohazard Supersites could be further improved by expanding the range of information available via the portals. Additional data is needed from other space agencies as well as from geological surveys, volcano observatories and other national agencies that provide ground-based seismic and GPS data. The Task team invites all of these data providers to become more actively involved in contributing to the Supersites.

In addition, mechanisms need to be put into place to facilitate the interaction between the researchers and the data providers to ensure that the key data is provided. For the Haiti earthquake, it was fortunate that UNAVCO was able to act quickly to play this critical role. To ensure that the Supersites system is robust and dependable, additional mechanisms must be secured in advance of the next major earthquake or volcanic event.