ANALYSIS of INDIAN REMOTE SENSING SATELLITE DATA for SIKKIM EARTHQUAKE (18 SEPT 2011) Earthquake Details (Source: USGS)

ANALYSIS OF INDIAN REMOTE SENSING SATELLITE DATA FOR SIKKIM EARTHQUAKE (18 SEPT 2011) Earthquake Details (Source: USGS)

Date Earthquake Epicentre Sunday, September 6.9 magnitude 27.723°N, 88.064°E 18, 2011 at 06:10:48 19.7 km (12.2 miles) PM at epicentre 68 km (42 miles) NW of Gangtok, Sikkim, India Sunday, September 4.8 magnitude 27.446°N, 88.391°E 18, 2011 at 06:41:57 20 km (12.4 miles) PM at epicentre 25 km (15 miles) WNW of Gangtok, Sikkim, India Sunday, September 4.6 magnitude 27.377°N, 88.266°E 18, 2011 at 07:24:18 20.1 km (12.5 miles) PM at epicentre 34 km (21 miles) W of Gangtok, Sikkim, India.

Major effected areas in India : Entire Sikkim (Mangan, Chungthang, Singtam, Gangtok etc.), North Bengal (Darjeeling, Kalimpong etc.) Details of analysis

• Pre and Post-earthquake Satellite data (optical and microwave) were acquired to assess the damage caused by the earthquake (Table 1).

• Optical data received within 24 hours were covered with cloud.

• All the microwave data (Table 1) acquired by NRSC and International charter were analysed for damage assessment. But microwave data could not be interpreted for damage and landslides because of foreshortening and layover effects due to ruggedness of the terrain.

• The latest cloud free IRS data sets were available on 29 and 30, September (Table 1) and the same were analysed for mapping the landslides which occurred after the event.

• Total 354 new landslides were mapped using pre and post CARTOSAT-1 stereo data sets. Table 1

Country Sensor Type Satellite Date of Acquisition Remark

India Optical Cartosat -2 (Mono) 19-sept-2011 Cloudy

India Optical Resourcesat-2 LISS 4 (Mono) 19-sept-2011 Cloudy

India Optical Resourcesat-2 AWiFS 19-sept-2011 Cloudy

Canada Microwave Radarsat-2 (C-band) 19-sept-2011 Layover and foreshortening effect because of terrain India Microwave RISAT-2 (X-band) 20-sept-2011 Layover and foreshortening effect because of terrain Germany Microwave TerraSAR-X (X-band) 21-sept-2011 Layover and foreshortening effect because of terrain India Optical Cartosat 2A 23-sept-2011 Cloudy

India Optical Cartosat-1 24-sept-2011 Cloudy Cartosat-2A Resourcesat-2 India Optical Cartosat-1 29-sept-2011 Partly cloudy

India Optical Cartosat-2B 30-sept-2011 Mostly cloud free

India Optical Resourcesat-2 LISS-IV Mx 03-oct-2011 Partly cloudy Synoptic view of Sikkim from Resourcesat-1 LISS III ± DONGKUNG "

THANGGU "

LACHEN # " Earthquake LACUNG epicentre "

CHUNGTHANG "

SAKKYONG " NADOM "

Mangan "

BRANG " PHENGTANG LINGMO " RALANG " GANGTOK " "

GEZING "

SINGTAM "

BHENOL " Namchi "

NAYA BAZAR " Area analysed for post-earthquake landslides using Cartosat-1 data of 30-sept-2011

0 4 8 16 24 32 Satellite image shown here is acquired on 13-apr-2005 Kilometers N " 0 ' 0

1 Landslide inventory in Sikkim after the earthquake ° 8 2

Details:

Date of event: 18 september 2011 Date of cloud free data acquisition: 29, 30 september 2011 Type of data: Cartosat-1 and Cartosat-2b ± No. of landslides identified: 354 new and 48 old landslides DONGKUNG " N " 0 ' 0 ° 8 2

THANGGU " N " 0 ' 0 5 ° 7 2

LACHEN "

LACUNG " N " 0 ' 0 4 ° 7

2 See figure 1

CHUNGTHANG " See figure 2 SAKKYONG " NADOM " See figure 3 N

" Mangan 0

' " 0 3

° See figure 4 7 2

See figure 5

BRANG " N " PHENGTANG LINGMO 0 " ' " RALANG GANGTOK 0 " " 2 ° 7 2 GEZING "

SINGTAM "

BHENOL " N " 0

' Namchi

0 " 1 °

7 Legend 2 NAYA BAZAR " Old landslides New landslides

0 4 8 16 24 32 See figures 1 to 5 for illustrations Kilometers 88°10'0"E 88°20'0"E 88°30'0"E 88°40'0"E 88°50'0"E Figure 1