Read each of the following and give a meaningful response in 3-5 sentences to each.
1. The Global disaster topic chosen for this assignment is the 2004 Indian Ocean Earthquake and Tsunami. Both tsunamis and tidal waves are seismic events. But tidal waves refer to astronomical tide waves and tsunami refers to earthquake driven waves (Elleman, 2007).
This earthquake was one of the largest to strike in history. The earthquake was called the Sumatra-Andaman of 26 December 2004. The eruption of this earthquake triggered a tsunami that was deemed to be the most devastating (at the time) in recorded history that resulted in the deaths of approximately 283,000 people (Lay, et.al, 2005). The death toll appears to be due to the densely populated region. The Sumatra-Andaman earthquake was measured at 9.0 – 9.3 magnitude and had the longest known earthquake rupture.
The Sumatra-Andaman earthquake that triggered the following tsunami struck the northern portion of the island of Sumatra, Indonesia (Taufiq Rafie et al., 2019). Due to the Sumatra island’s geographical location near a highly seismic active region between the Indo-Australian and Eurasian plates the area has approximately 4 or more seismic actions each year.
The risk consequence reduction of natural disasters is few. The author, Coppola wrote: “for natural disasters these measures are typically structurally based as achieved by hardening structures, implementing policies or passing laws and ordinances’” (2021, p.271). There are multiple seismic events yearly occurring in the region. I believe that the only true mitigation action to negate the consequences of possible tsunamis would be to relocate the population to other regions. Coppola wrote: “governments are facilitating the relocation of neighborhoods and even whole villages that have been built in zones of greatest risk from tsunamis, earthquakes, landslides, floods and other hazards” (2021, p.271). The changes that would be suggested are relocating coastal neighborhoods or communities farther inland to implement risk avoidance or at least minimize the consequences of the hazards.
In order to minimize risk in the future, United Nations Environment Programme (UNEP), amongst other organizations, has called for improved coastal management and rebuilding in safer places as well as in minimizing impacts on the environment. This is particularly relevant since the livelihood of the population depends on the quality of the environment: tourism, fishing and aquaculture are all economic activities requiring clean coasts and water (Chatenoux & Peduzzi, 2006, p.290). Mangroves forests are said to help in reducing the impacts from tsunamis (Khor 2005; Friend of the Earth 2005 as cited by Chatenoux & Peduzzi, 2006).
References
Chatenoux, B., Peduzzi, P. (2006). Impacts from the 2004 Indian Ocean Tsunami: Analysing the potential protecting role of environmental features. Natural Hazards, 40(2), 289–304. https://doi.org/10.1007/s11069-006-0015-9
Elleman, B. A. (2007). Waves of hope: The U.S. Navy’s response to the tsunami in Northern Indonesia. Naval war college Newport ri center for naval warfare studies.
Ishii, M., Shearer, P. M., Houston, H., & Vidale, J. E. (2005). Extent, duration and speed of the 2004 Sumatra–Andaman earthquake imaged by the Hi-Net Array. Nature, 435(7044), 933–936. https://doi.org/10.1038/nature03675
Lay, T., Kanamori, H., Ammon, C. J., Nettles, M., & al, e. (2005). The Great Sumatra-Andaman Earthquake of 26 December 2004. Science, 308(5725), 1127-33. https://ezproxy.library.astate.edu/login?qurl=https%3A%2F%2Fwww.proquest.com%2Fscholarly-journals%2Fgreat-sumatra-andaman-earthquake-26-december-2004%2Fdocview%2F213599952%2Fse-2%3Faccountid%3D8363
Taufiq Rafie, M., Sahara, D. P., Widiyantoro, S., & Dian Nugraha, A. (2019). Impact of the 2004 Sumatra-Andaman earthquake to the stress heterogeneity and seismicity pattern in Northern Sumatra, Indonesia. IOP Conference Series: Earth and Environmental Science, 318(1), 012010. https://doi.org/10.1088/1755-1315/318/1/012010
2. The Australian Tsunami Warning system was developed in 2009 in response to the extreme tsunami risk presented by 8000 km of active tectonic plate boundary (Paton, et al., 2017). This area is responsible for one-third of the world’s earthquakes and “can deliver tsunamis to the Australian coast within 2-4 hours” (Coppola, 2021).
The Joint Australian Tsunami Warning Centre (JATWC) provides tsunami warnings for each coastal zone categorized into three levels, no threat, marine threat, and land threat (Allen & Greenslade, 2016). The warning is based on inundation, “the horizontal distance inland that a tsunami penetrates, generally measured perpendicularly to the shoreline” (Pacific Coastal and Marine Science Center, 2010). The land threat warning “indicates that inundation is expected to occur within a costal zone, but it does not give any detailed information about the level of inundation” (Allen & Greenslade, 2016). This is a limitation of the JATWC system and is a ‘better safe than sorry’ model to provide a warning to the population.
This mitigation process is a detection system “designed to recognize a hazard that might not otherwise be perceptible to humans” (Coppola, 2021). Humans are unable to perceive a tsunami event until it is too late. “Advice and warnings are then issued as needed on any possible tsunami threat to state and territory emergency management services, media, and the public” (Coppola, 2021). This mitigation process neutralizes the threat posed to humans by creating alerts and warnings to evacuate an area. The system works but doesn’t prevent damage to property. Vehicles and equipment may be moveable, but structures remain susceptible to damage. Other mitigation processes could include relocation of affect populations, resistant construction, structural modification or construction of a barrier or deflection device. Relocation of large populated coastal areas is non-feasible and not cost effective to move the city of Sydney with 5.35 million people. A barrier or deflection device could provide some mitigation but limit shipping and travel by water capabilities.
The process works as it provides needed warning to the population. “Given that historical records are available for only a short period, there are no known events for which a land threat would have been issued for Australia” (Greenslade, et al., 2020). I agree with recommendations provided by Greenslade to provide “an action statement relating to the distance one needs to go inland to avoid danger, in addition to guidance as to the safe elevations above sea level” (2020). I would also add to ensure properly marked and designated evacuation routes are planned for each zone. A warning to evacuate is only useful if space and a path is provided. I’ve been unable to identify if any evacuation routes are designated for areas susceptible to a tsunami warning. New South Wales Emergency Service provides an evacuation map with higher elevation but doesn’t appear to identify roadways or pedestrian paths (2017).
References:
Allen, S. C. R., & Greenslade, D. J. M. (2016). A pilot tsunami inundation forecast system for australia. Pure and Applied Geophysics, 173(12), 3955-3971.
Coppola, D. P. (2021). Introduction to international disaster management (Fourth ed.). Butterworth-Hein.
Greenslade, D. J. M., Uslu, B., Allen, S. C. R., Kain, C. L., Wilson, K. M., & Power, H. E. (2020). Evaluation of australian tsunami warning thresholds using inundation modelling. Pure and Applied Geophysics, 177(3), 1425-1436.
King, D. (2008). How people responded to the april 2007 tsunami warning in cairns and townsville. Australian Journal of Emergency Management, 23(1), 10-20.
New South Wales State Emergency Service. (2017, February 2). Tsunami evacuation map. NSW State Emergency Service. Retrieved March 27, 2023, from https://www.ses.nsw.gov.au/resources-folder/tsunami-evacuation-map/
Paton, D., Johnston, D., Rossiter, K., Buergelt, P., Richards, A., & Anderson, S. (2017). Community understanding of tsunami risk and warnings in australia. Australian Journal of Emergency Management, 32(1), 54-59.
Pacific Coastal and Marine Science Center. (2010). Tsunami terms. Tsunami terms | U.S. Geological Survey. Retrieved March 24, 2023, from https://www.usgs.gov/media/images/tsunami-terms
