Mw7.2 Haiti Earthquake:

Sentinel-1 and ALOS-2 Interferometry

Descending Overview

Institute for Geophysics and Planetary Physics, University of California, San Diego, USA

IGPP nsf-logo

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.

The earthquake ruptured ~80 km from Nippes towards the west, in two main slip patches with primarily dip-slip in the east and strike slip in the west (USGS) (https://earthquake.usgs.gov/earthquakes/eventpage/us6000f65h/finite-fault). This pattern is clearly seen in the second interferogram with a large region of uplift in the east (towards the satellite in the LoS) and dominantly strike slip in the west (away from the satellite in the LoS. 

The EPGF is part of the system of strike slip and thurst faults that constitute the northeast boundary of the Caribbean tectonic plate. The plate boundary transitions from pure strike slip south of Cuba to subduction in the Antilles. The slip rate along the EPGF fault zone determined from GPS data is 10-11.4 mm/yr of oblique motion (Symithe et al., 2016). The rupture leaves a ~60 km segment of the EPGF unruptured between this and the 2010 Haiti M7.0 earthquake rupture on the Leogane fault (Symithe et al, 2015). Given the time since the historic earthquakes in 1701, 1751 and 1770 on this plate boundary (Manaker et al., 2008), there remains accumulated strain on the unruptured Mirogoane segment to the east of the August 14 event.


All Data

Most recent Google Earth project KMZ file

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)

Google drive folder containing all InSAR products to date



Sentinel-1 Descending track D142: 2021/08/03 - 2021/08/15

Descending coseismic interferogram

Download KMZ files for Google Earth: Phase + Coherence Layers + Line-of-Sight (Preliminary) Layers

PHASE
Phase
COHERENCE
Coherence
LOS (Preliminary)
LOS (Preliminary)

Sentinel-1 Ascending track A004: 2021/08/05 - 2021/08/17

Ascending coseismic interferogram

Download KMZ files for Google Earth: Phase + Coherence Layers + Unwrapped Phase (preliminary) Layers

PHASE
Phase
COHERENCE
Coherence
LINE OF SIGHT
LOS

Sentinel-1 Descending track D142: 2021/08/15 - 2021/08/21

Post-seismic Interferogram

Download KMZ files for Google Earth: Phase + Coherence Layers

PHASE
D142_phase
COHERENCE
Post-seismic descending
                                        coherence
LINE OF SIGHT
los

Sentinel-1 Ascending track A004: 2021/08/17 - 2021/08/23

Post-seismic Interferogram
Download KMZ files for Google Earth: Phase + Coherence Layers

PHASE
D142_phase
COHERENCE
Post-seismic descending
                                          coherence
LINE OF SIGHT
los

Sentinel-1 Descending track D142: 2021/08/21 - 2021/08/27

Post-seismic Interferogram

Download KMZ files for Google Earth: Phase + Coherence Layers
PHASE
A142 21-27 pair
COHERENCE
A142 21-27
                                                correlation
LINE OF SIGHT
los

Sentinel-1 Ascending track A004: 2021/08/23 - 2021/08/29

Post-seismic Interferogram
Download KMZ files for Google Earth: Phase + Coherence Layers
PHASE
A004 23-29 phase
COHERENCE
A004 23-29
                                                  coherence
UNWRAPPED PHASE (Not yet available)


Sentinel-1 Descending track D142: 2021/08/27 - 2021/09/02

Post-seismic Interferogram

Download KMZ files for Google Earth: Phase + Coherence Layers
PHASE
phase
COHERENCE
A142 21-27
                                                  correlation
UNWRAPPED PHASE (Not yet available)

Sentinel-1 Ascending track A004: 2021/08/29 - 2021/09/04

Post-seismic Interferogram
Download KMZ files for Google Earth: Phase + Coherence Layers
PHASE

COHERENCE

Line-of-Sight


Sentinel-1 Descending track D142: 2021/09/02 - 2021/09/08

Post-seismic Interferogram

Download KMZ files for Google Earth: Phase + Coherence Layers

Sentinel-1 Ascending track A004: 2021/09/04 - 2021/09/10

Post-seismic Interferogram
Download KMZ files for Google Earth: Phase + Coherence Layers







Acknowledgements:
We thank ESA for the rapid acquisition and distribution of their data. The development of the GMTSAR software, especially the processing chain for Sentinel-1 and ALOS-2, was supported by 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).