Coastal Changes in Nias Island and Banyak Islands,caused by 2005 Sumatra Earthquake
SUMMARY Emergence and Submergence: Coastal Change Inferred from Satellite Synthetic Aperture Radar Images(ENVISAT)
1. Coastal Change inferred from SAR
The image is derived from a comparison of intensity of reflected microwave observed by ESA ENVISAT satellite between February 4, 2005 (before Earthquake) and April 15, 2005 (after Earthquake).
2. Emergence
An area colored in cyan is a region where the reflective intensity is increased. The ribbons of cyan are distributed along the west coast of northwestern part of Nias Island and Bangkaru Island, Banyak Islands, Indonesia. The image indicates emergence of reefs or beaches due to uplift caused by a crustal deformation due to the March 28, 2005 Sumatra (Nias) , M8.7 earthquake.
The width of the cyan ribbon is about 1km at maximum.
The emergence had increased the size of small islets and even produced more than ten new small islets. The length of the maximum islet is approximately 1.5 km.
3. Submergence
An area colored in red is a region where the reflective intensity is decreased. The ribbons of red are distributed along the Tuangku Island, Banyak Islands, Indonesia. The image indicates submergence of reefs or beaches due to subsidence caused by a crustal deformation due to the 2005 Sumatra (Nias) earthquake.
4. Tide Level
Tide level at the northwestern Simeulue
-10 cm and -4 cm for the first and second image acquisition, respectively. |
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DETAIL Emergence and Submergence: Coastal Change Inferred from Satellite Synthetic Aperture Radar Images (ENVISAT)
Satellite and Sensor Specification and Tide Level
Radar data used here are acquired by ENVISAT ASAR (ESA).
Processed by GSI, Japan using GAMMA software.
observation time |
2005-02-04 15:51UTC |
2005-04-15 15:51UTC |
orbit |
Ascending |
beam |
IS6 |
incidence angle |
~ 41.5 degree |
microwave frequency |
5.33GHz (C band) |
wave length of microwave |
5.6235 cm |
polarization |
VV |
VV |
satellite altitude |
~ 787km |
data |
Signal Data (raw) |
tide level |
-10 cm |
-4 cm |
Details of Northwestern Nias Island
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