2University
of Texas Institute for Geophysics,
Austin, USA We compile Sentinel-1 and ALOS-2 repeat
acquisitions surrounding the time of the
2021 earthquake and use GMTSAR software to
process the raw data. Interferograms are
Gaussian filtered at 200 m and re-sampled at
50 m before further processing. We unwrap
the phase using the Statistical-Cost,
Network-Flow Algorithm for Phase Unwrapping
(SNAPHU), with nearest neighbor
interpolation over the low coherence areas
and water surfaces. The resulting LOS plots
below show surface deformation in the
line-of-sight of the observing satellite,
where positive indicates that the ground
pixel has moved towards the satellite. Download a Google Earth project file
containing all InSAR pairs included below as
layers. Also includes features picked from
these pairs and other published resources to
contextualize the InSAR data. Most
recent Google Earth project KMZ files Co & postseismic & secondary fault
structures Descending coseismic interferogram Ascending coseismic interferogram
Mw7.2 Nippes, Haiti
Earthquake:
Sentinel-1 and ALOS-2
Interferometry
H.
Zoe Yin1, Xioahua
Xu2, Jennifer
S. Haase1, David
T. Sandwell1
1Institute for Geophysics
and Planetary Physics, University of
California, San Diego, USA
The Mw7.2
Nippes, Haiti earthquake struck on August
14, 2021 (8:29 am local time)
on Haiti's southwest peninsula.
The earthquake occurred 125 km west of
Port-au-Prince at a depth of 10 km with an
oblique thrust faulting mechanism. The
earthquake occurred along the
Enriquillo-Plantain Garden fault (EPGF) zone,
about 100 km west of the Mw7.0
2010 Haiti earthquake.
Two InSAR satellites were operational before the
earthquake and continue to collect measurements
of line-of-sight (LOS) deformation. The C-band
Sentinel-1 satellites, operated by the European
Space Agency (ESA), provide a 6-day
coverage (ascending and descending tracks) of
the earthquake sequence. These data are
available on the Sentinel Data Hub. The
L-band ALOS-2 satellite, operated by the
Japanese Aerospace Exploration Agency (JAXA),
collected ascending ScanSAR data can be found on
the
ALOS-2 User Interface Gateway.
This page is to provide near-real time
line-of-sight deformation data from Sentinel-1
and ALOS-2. We will continue to provide images
for each repeat pass and update the
line-of-sight data once they are
available. The InSAR data are processed
with open source software GMTSAR
and mapped using Generic Mapping Tools (GMT).
The InSAR phase are filtered with a 300 m
Gaussian filter. The line-of-sight data are
acquired by merging different swaths' phase and
then unwrapped using snaphu. We
also include KMZ files for Google Earth with
some preliminary interpretation. These will be
updated as more remote sensing and field data
refines these interpretations.
Data
Google Earth Project Download
Download
full Google Earth project KMZ file
(update from 2022/03/20)
Download
full Google Earth project KMZ file
(update from 2021/09/07)
Download
full Google Earth project KMZ file
(update from 2021/09/03)
Download
full Google Earth project KMZ file (update
from 2021/08/23)
ALOS-2 Ascending Track 042 (Stripmap): Pair
2021/01/01 - 2021/08/27
PHASE: phasefilt_ll.grd
PHASE
GRADIENT: yphase_mask_ll.grd
LINE OF SIGHT: los_ll.grd
ALOS-2 Ascending Track 042 (Stripmap): Pair
2021/08/27 - 2021/12/31
Postsesismic & secondary fault structures
PHASE: phasefilt_ll.grd
PHASE
GRADIENT: yphase_mask_ll.grd
LINE OF
SIGHT: los_ll.grd
ALOS-2 Ascending Track 042 (Stripmap):
Pair 2021/01/01 -
2021/12/31
All Co & postseismic (Jan 1 - Dec
31)
PHASE: phasefilt_ll.grd
PHASE
GRADIENT: yphase_mask_ll.grd
LINE
OF SIGHT:
los_ll_dtr.grd
ALOS-2 Ascending Track 042 (Stripmap):
Phase gradient stack
The gradient of the phase taken
in the azimuth (flight) direction and stacked
using all ALOS-2 ascending track pairs between
Dec 23, 2020 and Dec 31, 2021 (3 pairs for A042
and 5 pairs for A043)
PHASE
GRADIENT
STACK: yphase_mask_ll_stack.grd
ALOS-2 Ascending Track 043
(Stripmap): 2020/12/23
- 2021/08/18
Coseismic
& surface rupture
PHASE:
phasefilt_ll.grd
PHASE
GRADIENT: yphase_mask_ll_2020-12-23_2021-08-18.grd
LINE OF
SIGHT: los_ll.grd
ALOS-2 Ascending Track 043 (Stripmap):
Phase gradient stack
The gradient of the phase
taken in the azimuth (flight) direction and
stacked using all ALOS-2 ascending track
pairs between Dec 23, 2020 and Dec 31, 2021
(3 pairs for A042 and 5 pairs for A043)
ALOS-2 Descending Track 138
(ScanSAR): 2019/12/10
- 2021/08/17
Coseismic
Deformation.
PHASE:
phasefilt_ll.grd
PHASE
GRADIENT: N/A
LINE
OF SIGHT:
los_ll_dtr.grd
ALOS-1 Ascending Track 138
(FBD): 2010/01/16
- 2010/06/23
2010
Postseismic Deformation
PHASE: phasefilt_ll.grd
PHASE
GRADIENT: yphase_mask_ll.grd
Sentinel-1 Descending track D142:
2021/08/03 - 2021/08/15
Download
KMZ files for Google Earth: Phase
+ Coherence Layers +
Line-of-Sight (Preliminary)
Layers
PHASE: phasefilt_ll.grd
Sentinel-1 Descending track D142:
2021/08/15 - 2021/08/21
Post-seismic
Interferogram
Download KMZ files
for Google Earth: Phase
+ Coherence Layers
Sentinel-1 Descending track
D142: 2021/08/21 - 2021/08/27
Post-seismic
Interferogram
Download
KMZ files for Google
Earth: Phase
+ Coherence
Layers
Sentinel-1 Ascending track A004: 2021/08/05
- 2021/08/17
Download
KMZ files for Google Earth: Phase
+ Coherence Layers
+ Unwrapped Phase (preliminary) Layers
Sentinel-1 Ascending track
A004: 2021/08/17 - 2021/08/23
Post-seismic
Interferogram
Download KMZ files for Google
Earth: Phase
+ Coherence Layers
PHASE: phasefilt_ll.grd
Sentinel-1 Ascending track
A004: 2021/08/23 - 2021/08/29
Post-seismic
Interferogram
Download KMZ
files for Google Earth: Phase
+ Coherence Layers
Acknowledgements:
Rapid
InSAR data processing was
supported by a National
Science Foundation RAPID grant
(Grant #2150704). We
thank the operators of the
Ayiti-Séismes earthquake monitoring
network at Bureau des Mines, Faculté
des Sciences, Laboratoire URGéo,
Université d'état d'Haïti, Ecole
Normale Supérieur, and Laboratoire
Géoazur for making aftershock
locations free and openly available.
We thank Roby Douilly at the
University of California Riverside
for contributions to aftershock
relocations and interpretation of
our results. We thank Bernard
Mercier de Lepinay for contributions
in the interpretation of our results
in the geologic context. We thank
Sylvert Paul and Francoise
Courboulex at GéoAzur, Eric Calais
at ENS, and Jeremy Maurer at
Missouri University of Science and
Technology for helpful discussions
related to the earthquake. We thank
ESA for the rapid acquisition and
distribution of Sentinel-1 data. We
thank JAXA for access to ALOS-1 and
ALOS-2 data. The development of the
GMTSAR software, and specifically
the processing chain for Sentinel-1
and ALOS-2, was supported by the
National Aeronautics and Space
Administration (NASA) and the
National Science Foundation through
the NASA Earth Surface and Interior
program (NNX16AK93G and
80NSSC19K1043), the NSF Office of
Advanced Cyberinfrastructure program
(OAC-1834807), and the NSF
EarthScope program (EAR-1147435,
EAR-1424374, EAR-1614875).