LAND
MARINE
ATMOSPHERE
EMERGENCY MANAGEMENT
CLIMATE CHANGE
SECURITY
ISSUE 32 / SEPTEMBER 2013
HOW SATELLITES CAN MEASURE TERRAIN
DISPLACEMENTS AFTER EARTHQUAKES
Earthquakes reaching 5.9 on the Richter scale hit the northern Italian region of Emilia
Romagna on 20 and 29 May 2012. The earthquakes caused 27 fatalities, an estimated
350 people were injured and over 43 000 people had to be put up in temporary
accommodation. Historical buildings, infrastructure and the region's economy
suffered serious damage as a result of the quakes. Like other countries in the central
and eastern Mediterranean and in the Balkan Peninsula, Italy lies in a seismically
active region, has a dense population and many historical buildings so is at great
risk when catastrophic events occur. The Emilia Romagna earthquake, caused by a
displacement of the African plate towards the Eurasian plate, was even felt in Austria,
Croatia, Slovenia, southeast France, southern Germany and Switzerland. It generated
terrain deformations of several centimetres.
Copernicus satellites can help to precisely measure deformation of the
Earth's surface following an earthquake and to support related seismological
analyses.
Complementing ground information, satellites provide frequent, synoptic views of areas in crisis to provide
the bigger picture of where the ground has moved. In particular, spaceborne Synthetic Aperture Radars (SARs)
are capable of measuring terrain displacements down to millimetres. Displacements can indicate activity in
underground faults and such information can support the analyses of vulnerability and site-specific hazards.
These data are used to update risk maps and are especially useful when reconstruction is underway. The
integration of all available independent measurements (in situ and from space) is considered instrumental
for supporting research efforts by the global scientific community and to improve our understanding of the
tectonic processes.
Epicentre
29th of May
5,5 - 5,9
5,1 - 5,4
4,1 - 5,0
2,5 - 4,0
www.esa.int/copernicus • http://copernicus.eu/
The image shows the terrain deformations
caused by the 29 May earthquake in Emilia
Romagna (Italy) as obtained by processing
satellite data. The colour shading highlights
displacements of up to 20 cm (red) around
the epicentre, but also an area of slight
subsidence (blue) some kilometres
eastwards. In addition to the two main
shocks of May 20 and May 29, the Emilia
Romagna event was characterised by a large
seismic strain. Several shocks of magnitude
larger than 2.5 on the Richter scale were
registered in the area in the same period:
for these, the epicentres locations are
shown on the map by means of white circles.
Source: Istituto Nazionale di Geofisica e Vulcanologia (INGV).
Satellite Data: Cosmo-SkyMed
Facts
> Each claiming more than
200.000 lives, the 2004
Indian Ocean earthquake
and the 2010 Haiti
earthquake have been the
most deadly so far this
century
> In the last 15 years, almost
5.000 people have died in
earthquakes in countries of
the EU
> The most seismically active
regions in Europe are in
the Mediterranean area (in
particular, Greece, Italy and
southern Spain, Turkey) and
in some parts of Eastern
Europe and the Balkans
Benefits
Satellite measurements of
ground displacement help to:
> improve models of what
happens during an
earthquake
> improve the understanding
about tectonic processes,
especially with respect to
hidden faults and in remote
regions
Policy Objectives
> International Strategy for
Disaster Reduction (ISDR)
> EU Council Regulation on
Humanitarian Aid
> Community Mechanism for
Civil Protection
> EUR-OPA Major Hazards
Agreement
ISSUE 32 / SEPTEMBER 2013
COPERNICUS
ACTIVITIES
Copernicus services
Sentinel contribution
Next steps
The Copernicus Emergency Management
Service makes use of satellite data to
support damage assessment following
disasters.
The Copernicus Sentinel-1 mission will
increase the capability for monitoring by
providing Synthetic Aperture Radar (SAR)
imagery, supporting:
> Create and maintain tectonic strain
maps and seismic hazard maps based on
systematic SAR acquisitions
Example products:
> operational, routine monitoring of
vulnerable areas at high spatial resolution
> Rapid mapping reference maps
> Delineation and grading maps
> Pre- and post- disaster situation maps
> all-weather, day-and-night measurements
> constant and regular acquisition to build a
large global archive
> wide area coverage, thanks to the 250 km
image swath width
> Improve models of earthquake cycles fully
integrating available Earth observation
and GNSS data
> Improve the rapid and automated
production of SAR-based earthquake
displacement maps to support
aftershocks hazard analyses
> Integrate satellite-based terrain
displacement products in crisis
management activities
Sentinel-1
Observing how the Earth surface moves
Epicentre
29th of May
Epicentre
20th of May
The Copernicus Sentinel-1 mission carries a SAR that will provide
detailed measurements of terrain displacements worldwide.
This is made possible through a processing technique called
SAR interferometry (InSAR). The technique is based on making a
comparison between phase measurements of SAR acquisitions
of the same place taken over time, similar to a sophisticated
version of 'spot the difference'. Sentinel-1, with its improved
regular acquisition coverage, will play a key role in advancing
interferometry. The first Sentinel-1 satellite is expected to be
ready for launch in 2014 and will be followed by a second satellite
shortly after to fulfil Copernicus coverage needs.
This image is an interferogram of the Emilia Romagna earthquakes in May 2012.
The irregular, rainbow coloured patterns of the interferogram highlight the surface
displacements, the amount of which is proportional to the spatial frequency of the
fringes. In the image, hotspots of vertical displacements are evident in the large
number of fringes around the locations of the epicentres.
The interferogram was generated using data from RADARSAT-1, which is a Copernicus
contributing mission carrying a SAR instrument similar to that of Sentinel-1.
Source: Tele-Rilevamento Europa (TRE)
www.esa.int/copernicus • http://copernicus.eu/