Tsunami Impact on Populated Coastlines of Sumatra and Java

Tsunami travel times. (a) Distribution of maximum tsunami amplitudes based on the tsunami model by Heidarzadeh et al. (2020). The dashed lines are tsunami travel times in hours with 15-min intervals. The star shows the Anak Krakatau Volcano source. The triangles are the locations of tide gauge stations. (b) Tide gauge waveforms of the tsunami in various stations. (c–e) Snapshots of tsunami propagation over time. From Heidarzadeh et al., (2020).

The travel time of the tsunami across the Sunda Strait was calculated from tide gauge data, with the time of generation estimated from satellite imagery and seismic signals. The tsunami first arrived on the populated coastline of Banten, island of Java, about 32 minutes after the collapse (Marina Jambu station, 45 km due east of Anak Krakatau),and at Ciwanden station, northwest Banten, (60 km from the source) at 48 minutes. Differences in water depth and wave interference by islands and bathymetric features influenced travel times. Propagation through the deeper water to Kota Agung on southwest Lampung, island of Sumatra, took only 43 minutes, even though it is 50 km more distant than Ciwanden, and 40 km more distant than the Pangang station on Sumatra where arrival took 55 minutes.

The largest boulder found in Cipenyu Beach of Banten was transported about 87m from its
original place. An arrow shows the estimated transport direction of the boulder with an
estimated velocity of 4.37m/s, captured on 28 December 2018. (Syamsidik et al., 2020)

Wave height, time, and distance from source of first impacts at local tide gauges (Heidarzadek et al., 2020; Syamsidik et al., 2020):

Mark of tsunami flow depth observed on wall of broken houses in
(a) Anyer and (b) Sumur, showing highest flow depth. (Putra et al., 2020)

(https://nhess.copernicus.org/articles/20/549/2020/nhess-20-549-2020.pdf; full data set at https://data.mendeley.com/datasets/yyyvmxh8vg/1)

• Maximum tsunami wave heights (calculated from flow depth + land elevation):
  • 6.6 m, Samolo Bay, Banten, ~ 50 km ESE of source
  • 9.6 m, Cipeyu Beach, Banten, ~ 50 km SSE of source

• Maximum flow depth: 6.6 m, Cipeyu Beach, Banten
• Maximum run-up: 14.9 m above mean sea level, Sumur, Banten, ~ 65 km SSE of source
• Maximum inundation distance: 259 m, Samolo Bay, Banten
  
  

Observed tsunami damage in Sumur area: (a) heavily damage in traditional market area;
(b) damaged front wall house with flow depth around 2 m
(c) heavy damage to fishing port; and
(d) fishing boat transported inland around 80 m in the north of fishing port. (Putra et al.,2020)

The Indonesian National Board for Disaster Management (Badan Nasional Penanggulangan Bencana, BNPD) reported final statistics on casualties and damage (31 January 2019):

• Deaths: 437
• Injuries: 14,059
• Missing: 10
• Displaced/Evacuated: 16,198 
• Severe property damage: 1,614 (includes 97 hotels and 510 boats)
• Partly damaged property: 527
• Lightly damaged property: 97

Contents

• History
• Post-tsunami Eruptions and Cone Regrowth
• 22 December 2018 Eruptions and Tsunami
• Tsunami Impact on Nearby Unpopulated Islands
• Tsunami Impact on Populated Coastlines of Sumatra and Java
• Tsunamagenic Flank Failure Scenarios
• Seismic Signals, Early Warning Wystems and Event Documentation
• Lessons Learned
• Event Information
• Krakatau Islands History
• Media Reports, Photos and Video
• Research Articles