On August 10th, a more than 1,000 foot high megatsunami was generated 59 miles southeast of the city of Juneau within Alaska. While the worst of this wave was completely confined to the Tracy Arm (fjord), evidence shows that the seiche from this landslide generated megatsunami continued sloshing back and forth across a 1,100 meter stretch of water for nearly 35 hours. Do note that this did not cause 1,000 feet or more of run-up for this entire 35 hour long duration. Thumbnail Photo Credit: This work "Wave100", is a derivative of a photo (resized, cropped, decreased brightness of bright areas in image, increased darkness of dark areas in image, text overlay, overlaid with GeologyHub made graphics (the image border & the GeologyHub logo)) from "Glass Ceiling", by: James Loesch, jal33, 2016, Posted on Flickr, Flickr account link: https://www.flickr.com/photos/jal33/, Photo link: https://www.flickr.com/photos/jal33/28235826616, CC BY 2.0. "Wave100" is used & licensed under CC BY 2.0 by Youtube.com/GeologyHub Google Earth imagery used in this video: ©Google & Data Providers This video is protected under "fair use". If you see an image and/or video which is your own in this video, and/or think my discussion of a scientific paper (and/or discussion/mentioning of the data/information within a scientific paper) does not fall under the fair use doctrine, and wish for it to be censored or removed, contact me by email at [email protected] and I will make the necessary changes. Various licenses used in sections of this video (not the entire video, this video as a whole does not completely fall under one of these licenses) and/or in this video's thumbnail image (and this list does not include every license used in this video and/or thumbnail image): Public Domain: https://creativecommons.org/publicdomain/mark/1.0/ CC BY 2.0: https://creativecommons.org/licenses/by/2.0/legalcode CC BY 4.0: https://creativecommons.org/licenses/by/4.0/legalcode Sources/Citations: [1] U.S. Geological Survey [2] Monahan, T., Tang, T., Roberts, S. et al. Observations of the seiche that shook the world. Nat Commun 16, 4777 (2025). https://doi.org/10.1038/s41467-025-59851-7, CC BY 4.0. [3] Heidarzadeh, Mohammad & Rabinovich, Alexander & Kusumoto, Satoshi & C. P., Rajendran. (2020). Field surveys and numerical modelling of the 2004 December 26 Indian Ocean tsunami in the area of Mumbai, west coast of India. Geophysical Journal International. 222. 1952-1964. 10.1093/gji/ggaa277. CC BY 4.0. [4] Rauter, M., Viroulet, S., Gylfadóttir, S.S. et al. Granular porous landslide tsunami modelling – the 2014 Lake Askja flank collapse. Nat Commun 13, 678 (2022). https://doi.org/10.1038/s41467-022-28296-7, CC BY 4.0. [5] Alaska Earthquake Center [6] NOAA [7] 2020, Strzelecki, M. C. and Jaskólski, M. W., European Geosciences Union; Arctic tsunamis threaten coastal landscapes and communities – survey of Karrat Isfjord 2017 tsunami effects in Nuugaatsiaq, western Greenland, Nat. Hazards Earth Syst. Sci., 20, 2521–2534, https://doi.org/10.5194/nhess-20-2521-2020, 2020. CC BY 4.0. [8] D. Miller, “Giant Waves in Lituya Bay Alaska”, USGS, Geological Survey Professional Paper 354-C. [9] 2018, Higman, B., Shugar, D.H., Stark, C.P. et al, Springer Nature, Scientific Reports.; The 2015 landslide and tsunami in Taan Fiord, Alaska. Sci Rep 8, 12993 (2018). https://doi.org/10.1038/s41598-018-30475-w, CC BY 4.0 [10] Schöpa, A., Chao, W.-A., Lipovsky, B. P., Hovius, N., White, R. S., Green, R. G., and Turowski, J. M.: Dynamics of the Askja caldera July 2014 landslide, Iceland, from seismic signal analysis: precursor, motion and aftermath, Earth Surf. Dynam., 6, 467–485, https://doi.org/10.5194/esurf-6-467-2018, 2018., CC BY 4.0 [11] Marzban Pouria, Bredemeyer Stefan, Walter Thomas R., Kästner Friederike, Müller Daniel, Chabrillat Sabine, "Hydrothermally altered deposits of 2014 Askja landslide, Iceland, identified by remote sensing imaging", Frontiers in Earth Science, Volume 11, 2023, https://www.frontiersin.org/articles/10.3389/feart.2023.1083043, DOI: 10.3389/feart.2023.1083043, ISSN: 2296-6463, CC BY 4.0 [12] Donati D, Stead D, Geertsema M, Bendle JM, Menounos B and Borgatti L (2022) Kinematic Analysis of the 2020 Elliot Creek Landslide, British Columbia, Using Remote Sensing Data. Front. Earth Sci. 10:916069. doi: 10.3389/feart.2022.916069 [13] Franco, Andrea & Schneider-Muntau, Barbara & Roberts, Nicholas & Clague, John & Gems, Bernhard. (2021). Geometry-Based Preliminary Quantification of Landslide-Induced Impulse Wave Attenuation in Mountain Lakes. Applied Sciences. 11. 11614. 10.3390/app112411614., CC BY 4.0. [14] Jiajia Wang, Steven N. Ward, Lili Xiao, Numerical simulation of the December 4, 2007 landslide-generated tsunami in Chehalis Lake, Canada, Geophysical Journal International, Volume 201, Issue 1, April 2015, Pages 372–376, https://doi.org/10.1093/gji/ggv026 0:00 Alaska Megatsunami 0:39 Seiche 2:17 More Studies Needed 3:31 Wave Height vs Run-Up