https://meetingorganizer.copernicus.org/EGU2020/EGU2020‐11838.html Field Survey of the 2018 Anak KrakatauFritz et al., 2020 Tsunami on the Islands in the Hermann M. Fritz1, Tubagus Solihuddin2, Costas E. Synolakis3,4, Gegar S. Prasetya5, Jose C. Borrero6, Vassilis Skanavis3, Semeidi Husrin2, Widjo Kongko7, Dinar C. Istiyanto7, August Daulat2, Dini Purbani2, Hadiwijaya L. Salim2, Rahman Hidayat2, Velly Asvaliantina2, Maria Usman5, Ardito Kodijat9

1 School of Civil and Environmental Eng., Georgia Institute of Technology, Atlanta, GA 30332, USA 2 Marine Research Centre, Ministry of Marine Affairs and Fisheries, Jakarta 14430, 3 Dept. of Civil and Env. Eng., University of Southern California, Los Angeles, CA 90089, USA 4 Dep. of Environmental Engineering, Technical University of Crete, Chanea 73100, Greece 5 Indonesian Tsunami Scientific Community, Jakarta 12950, Indonesia 6 eCoast Ltd., 47 Cliff St., Raglan 3225, New Zealand 7 Agency for the Assessment and Application of Technology (BPPT), Yogyakarta 55284, Indonesia 8 Coordinating Ministry for Maritime Affairs – Jakarta 10340, Indonesia 9 IOC‐UNESCO, Indian Ocean Tsunami Information Center (IOTIC), Jakarta 12110, Indonesia 1 Volcanic Tsunamis: Fritz et al., 2020 Krakatau 1883 and 2018

Krakatau 1883 remnant Rakata Anak Krakatau Before (Photo: September 2018) VolcanicAnak Krakatau Tsunamis Before –Krakatau 1883 (Photos: September 2018)

Fritz et al., 2020 Meeting at Marine Research Center (MRC): Fritz et al., 2020 Ministry of Marine Affairs and Fisheries (MoMAF) and Coordinating Ministry of Maritime Affairs (CMoMA)

4  TIDE STATION POINTS

Slide: Widjo Kongko

#Lon. (deg) Lat. (deg.) Sta. Name G.A.K 1 105.8410 ‐6.1893 Serang 2 105.9530 ‐6.0176 Ciwandan 3 104.2130 ‐5.5204 Bangkunat 4 104.6190 ‐5.5003 Kota Agung 5 105.3190 ‐5.4713 Panjang

Fritz et al., 2020 Fritz et al., 2020

G.A.K  MARIGRAM: Ciwandan Slide:0.80 0.60 Widjo Kongko 0.40 Ciwandan 0.20 (m)

(105.953E, 6.0176S) 0.00

‐0.20 Elevation

7:00:00 8:00:00 9:00:00 0:00:00 1:00:00 2:00:00 3:00:00 4:00:00 5:00:00 6:00:00 7:00:00

‐0.40 10:00:00 11:00:00 12:00:00 13:00:00 14:00:00 15:00:00 16:00:00 17:00:00 18:00:00 19:00:00 20:00:00 21:00:00 22:00:00 23:00:00

‐0.60Water

‐0.80 22/12/2018 22/12/2018 22/12/2018 23/12/2018 23/12/2018 23/12/2018 23/12/2018 23/12/2018 23/12/2018 23/12/2018 23/12/2018 ‐1.00 22/12/2018 22/12/2018 22/12/2018 22/12/2018 22/12/2018 22/12/2018 22/12/2018 22/12/2018 22/12/2018 22/12/2018 22/12/2018 22/12/2018 22/12/2018 22/12/2018 Time (UTC+7:00 / WIB) Ciwandan 1 (105.953E, 6.0176S) 0.8

0.6 (m) 0.4

0.2 Elevation

0 Water ‐0.2 0:00:00 1:00:00 2:00:00 3:00:00 4:00:00 5:00:00 6:00:00 7:00:00 7:00:00 8:00:00 9:00:00

10:00:00 11:00:00 12:00:00 13:00:00 14:00:00 15:00:00 16:00:00 17:00:00 18:00:00 19:00:00 20:00:00 21:00:00 22:00:00 23:00:00 ‐0.4

‐0.6 Time (UTC+7:00 / WIB) 23/12/2018 23/12/2018 23/12/2018 23/12/2018 23/12/2018 23/12/2018 23/12/2018 23/12/2018 22/12/2018 22/12/2018 22/12/2018 2/12/2018 2/12/2018 2/12/2018 2/12/2018 2/12/2018 2/12/2018 2/12/2018 2/12/2018 2/12/2018 2/12/2018 2/12/2018 2/12/2018 2/12/2018 2/12/2018 2 2 2 2 2 2 2 2 2 2 2 2 2 2 Sunda Strait Islands Tsunami Field Survey

7 Rakata Island

Maximum 85 m runup

8 Fritz et al., 2020 Rakata Island Fritz et al., 2020

9 Rakata Island Fritz et al., 2020

10 Rakata Island Fritz et al., 2020

11 Rakata Island Fritz et al., 2020

12 Rakata Island Fritz et al., 2020

13 Rakata Island Fritz et al., 2020

14 Rakata Island Fritz et al., 2020

15 Rakata Island Fritz et al., 2020

16 Rakata Island Fritz et al., 2020

17 Fritz et al., 2020 Rakata Island

18 Rakata Island Fritz et al., 2020

19 Krakatau Volcanic Complex

20 Fritz et al., 2020 Panjang Island Fritz et al., 2020

21 Panjang Island Fritz et al., 2020

22 Panjang Island Fritz et al., 2020

23 Anak Krakatau Fritz et al., 2020

24 Anak Krakatau Volcano Fritz et al., 2020

25 Sertung Island Fritz et al., 2020

Rakata

Anak Krakatau

26 Sertung Island Fritz et al., 2020

27 Sertung Island Fritz et al., 2020

28 Sertung Island Fritz et al., 2020

29 Sertung Island Fritz et al., 2020

30

Nearest Inhabited Island

31 Fritz et al., 2020 Sebesi Island Fritz et al., 2020

32 Sebesi Island Fritz et al., 2020

33 Sebesi Island Fritz et al., 2020

34 Sebesi Island Fritz et al., 2020

35 Waymuli, Fritz et al., 2020

36 Fritz et al., 2020 Waymuli, Sumatra

37 Panaitan Island, Ujung Kulon National Park

38 Fritz et al., 2020 Panaitan Island, Ujung Kulon National Park Fritz et al., 2020

39 Panaitan Island, Ujung Kulon National Park

40 Fritz et al., 2020 Panaitan Island, Ujung Kulon National Park

41 Fritz et al., 2020 Ujung Kulon National Park

42 Fritz et al., 2020 Ujung Kulon National Park Fritz et al., 2020

43 Ujung Kulon National Park Fritz et al., 2020

44 Ujung Kulon National Park Fritz et al., 2020

45 Eyewitness Interview Fritz et al., 2020

46 Sunda Strait Islands Tsunami Field Survey

47 Fritz et al., 2020 2018 Sunda Strait tsunami CONCLUSIONS Fritz et al., 2020 • ITST collected 87 tsunami heights February 4‐9, 2019 • Maximum 85 m runup on Rakata and an 83 m runup on Sertung. • Flow depth reached more than 11 m above ground on Sertung. • On Sebesi Island located 15 km northeast of the source tsunami runup heights remained below 10 m. • Tsunami heights exceeding 10 m were observed in the Ujung Kulon National Park located 50 km southwest. • The runup distributions on the islands encircling Anak Krakatau highlight the directivity of the collapse towards the southwest. • Inundation and damage were mostly limited to within 400 m of the shoreline given the relatively short wavelengths of volcanic tsunamis. • The team interviewed numerous eyewitnesses based on established protocol and educated residents about tsunami hazards. • Community‐based education and awareness programs are essential to save lives in locales at risk from locally generated tsunamis. • Regrowth of Anak Krakatau will determine the future tsunami hazard • PAGEOPH Borrero et al., 2020 tentatively accepted for publication Acknowledgments Fritz et al., 2020

This work is supported by • National Science Foundation NSF RAPID award CMMI‐1906162 • Any opinions, findings, and conclusions or recommendations expressed herein are those of the author(s) and do not necessarily reflect the views of the National Science Foundation Terima Kasih ‐ Questions Fritz et al., 2020