International Tsunami Survey Team Research Articles

Hard Lessons of the 2018 Indonesian Tsunamis

Within 4 months of 2018, two fatal tsunamis struck islands of Indonesia with ferocity that astonished local population, tsunami warning systems and scientists. For both of these events, the September 28 Palu Bay tsunami in Sulawesi and the 22 December Anak Krakatau tsunami in Sunda Strait, the initial tsunami source data was either non-suggestive or simply non-existent to imply such a devastating wave impact. International teams of scientists, members of the International Tsunami Survey Team, descended to Indonesia to help local scientists collecting all possible data from these two events, investigating the origins of these tsunamis to explain the unexpected tsunami strength. The analysis of the observation data presented in this collection of papers mostly explains the unexpectedly devastating impact from these two unusual tsunami events. The lessons learned from the response to these two events coupled with the new scientific understanding of tsunami genesis will provide improved guidance for more effective tsunami warning operations for Indonesia and the coastlines around the World.

Field Survey and Numerical Modelling of the December 22, 2018 Anak Krakatau Tsunami

On December 22, 2018, the eruption and flank collapse of the Anak Krakatau volcano generated a tsunami in the Sunda Strait causing catastrophic damage to uninhabited coastlines proximal to the source. Along the heavily populated shores of Banten and Lampung provinces in Java and Sumatra, tsunami waves caused severe damage, extensive inundation and more than 430 deaths. An international tsunami survey team (ITST) deployed 6 weeks after the event documented the tsunami effects including runup heights, flow depths and inundation distances, as well as sediment deposition patterns and impacts on infrastructure and the natural environment. The team also interviewed numerous eyewitnesses and educated residents about tsunami hazards. This ITST was the first to visit and document the extreme tsunami effects on the small islands in the Sunda Strait closest to Anak Krakatau (Rakata, Panjang, Sertung, Sebesi and Panaitan). Along the steep slopes of Rakata and Sertung islands, located less than 5 km from and facing directly towards the southwest flank of Anak Krakatau, all of the dense coastal vegetation was stripped to bare earth up to elevations of more than 80 m, while on the northeast tip of Sertung Island, facing away from the source, a single tree remained standing after flow depths of > 11 m above ground struck there. The runup distributions on the islands encircling Anak Krakatau highlight the directivity of the tsunami source suggesting that the collapse occurred towards the southwest. This manifested as tsunami runup of 10 m that stripped away coastal forests to bare rock for up to 400 m inland in the Ujung Kulon National Park, located 50 km to the south-southwest. Inundation and damage were mostly limited to within 400 m of the shoreline, likely the result of the relatively short wavelengths caused by the landslide generated tsunami. A significant variation in tsunami impact was observed along the shorelines of the Sunda Strait, with runup heights rapidly decreasing with distance from the inferred tsunami source. To model the event we applied a hot-start initial condition that roughly reproduced the measured tsunami runup heights along Rakata and Sertung. The waveforms were then propagated through the Sunda Straight using a Boussinesq-type wave model. The results showed a good fit to the observed heights along the Java and Sumatra coastlines, the northern coast of Panaitan Island and Ujung Kulon Nation Park. The model also produced an acceptable fit to the observed amplitudes at tide gauges. Despite the regional volcanic and tsunamigenic history of the region, and 6-months of eruptive activity prior to the event, the tsunami largely caught the local population off guard. This further highlights the need for community-based education and awareness programs as essential to save lives in locales at risk from locally generated tsunamis.

The Impact of Post-tsunami Surveys on the NCEI/WDS Global Historical Tsunami Database

Since the late nineteenth century, post-tsunami survey teams have been collecting water height data (e.g. maximum inundation, runup, flow depth) as well as other types of data, including geologic and socio-economic effects. The NOAA National Centers for Environmental Information (NCEI) and co-located World Data Service (WDS) for Geophysics provide data management and access to global tsunami data. NCEI’s Global Historical Tsunami Database includes information on over 2200 tsunami sources and over 26,000 runup points. The tsunami database has adapted to capture the advancements of post-tsunami survey data collection and distribution methods. The first International Tsunami Survey Team (ITST), which surveyed the impacts of the 02 September 1992 Nicaragua tsunami, spurred the formalization of standards and guidance for post-tsunami surveys. The post-tsunami survey data analyzed are a significant contribution, in quality and quantity, to the runup database. The 26 December 2004 Indonesia and 11 March 2011 Japan events alone account for over 25% of the total number of runup points in the database. Further, the analysis indicates that post-tsunami survey data capture a more complete representation of the tsunami that is being documented, not just the highest runup measurements. This range in post-tsunami survey runup heights for events, in the NCEI/WDS tsunami database, provides a more reliable historical tsunami dataset to test tsunami models against. This study also provides readers an understanding of the evolution of the tsunami database, particularly regarding the ongoing need to adapt to emerging scientific advances and standards.

The September 28th, 2018, Tsunami In Palu-Sulawesi, Indonesia: A Post-Event Field Survey

On September 28th, 2018, a powerful earthquake (Mw 7.5) struck the Island of Sulawesi in Indonesia. The earthquake was followed by a destructive and deadly tsunami that hit the Bay of Palu. A UNESCO international tsunami survey team responded to the disaster and surveyed 125 km of coastline along the Palu Bay up to the earthquake epicentre region. The team performed 78 tsunami runup and inundation height measurements throughout the surveyed coastline. Measured values reached 9.1 m for the runup height and 8.7 m for the inundation height, both at Benteng village. The survey team also identified ten large coastal sectors that collapsed into the sea of Palu Bay after the earthquake. The distribution of the measured tsunami data within Palu Bay exhibits a clear localised impact suggesting the contribution of secondary non-seismic local sources to the generation of the tsunami. Findings of the field reconnaissance are discussed to provide an insight into the remaining debated source of the Palu tsunami.

Tsunami Waves of Destruction: The Creation of the “New Australian Catastrophe”

Tsunami Waves of Destruction: The Creation of the “New Australian Catastrophe”

Twin Tsunamis Triggered by the 12 January 2010 Haiti Earthquake

On 12 January 2010, a magnitude M w 7.0 earthquake occurred 25 km west–southwest of Haiti’s capital Port-au-Prince causing an estimated 316,000 fatalities, thereby exceeding any previous loss of life from a similar size earthquake. In addition, tsunami waves triggered by the earthquake caused at least three fatalities at Petit Paradis due to a complete lack of tsunami awareness. The International Tsunami Survey Team (ITST) was deployed within weeks of the event and covered the greater Bay of Port-au-Prince and more than 100 km of Hispaniola’s southern coastline. The collected survey data include more than 21 tsunami heights along with observations of coastal land level change. Maximum tsunami heights of 3 m have been measured for two independently triggered tsunamis.

Field Survey of the 27 February 2010 Chile Tsunami

On 27 February 2010, a magnitude Mw = 8.8 earthquake occurred off the coast of Chile’s Maule region causing substantial damage and loss of life. Ancestral tsunami knowledge from the 1960 event combined with education and evacuation exercises prompted most coastal residents to spontaneously evacuate after the earthquake. Many of the tsunami victims were tourists in coastal campgrounds. The international tsunami survey team (ITST) was deployed within days of the event and surveyed 800 km of coastline from Quintero to Mehuin and the Pacific Islands of Santa Maria, Mocha, Juan Fernandez Archipelago, and Rapa Nui (Easter). The collected survey data include more than 400 tsunami flow depth, runup and coastal uplift measurements. The tsunami peaked with a localized runup of 29 m on a coastal bluff at Constitucion. The observed runup distributions exhibit significant variations on local and regional scales. Observations from the 2010 and 1960 Chile tsunamis are compared.

Field Survey of the Samoa Tsunami of 29 September 2009

Research Article| July 01, 2010 Field Survey of the Samoa Tsunami of 29 September 2009 Emile A. Okal; Emile A. Okal Department of Earth and Planetary Sciences Northwestern University Evanston, Illinois 60208 U.S.A. emile@earth.northwestern.edu (E. A. O.) 1Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL 60208 Search for other works by this author on: GSW Google Scholar Hermann M. Fritz; Hermann M. Fritz Department of Earth and Planetary Sciences Northwestern University Evanston, Illinois 60208 U.S.A. emile@earth.northwestern.edu (E. A. O.) 2School of Civil and Environmental Engineering, Georgia Institute of Technology, Savannah, GA 31407 Search for other works by this author on: GSW Google Scholar Costas E. Synolakis; Costas E. Synolakis Department of Earth and Planetary Sciences Northwestern University Evanston, Illinois 60208 U.S.A. emile@earth.northwestern.edu (E. A. O.) 3Department of Civil Engineering, University of Southern California, Los Angeles, CA 90089 4Department of Environmental Engineering, Technical University of Crete, 73100 Chania, Greece Search for other works by this author on: GSW Google Scholar José C. Borrero; José C. Borrero Department of Earth and Planetary Sciences Northwestern University Evanston, Illinois 60208 U.S.A. emile@earth.northwestern.edu (E. A. O.) 3Department of Civil Engineering, University of Southern California, Los Angeles, CA 90089 5ASR Ltd., 1 Wainui Road, Raglan 3225, New Zealand Search for other works by this author on: GSW Google Scholar Robert Weiss; Robert Weiss Department of Earth and Planetary Sciences Northwestern University Evanston, Illinois 60208 U.S.A. emile@earth.northwestern.edu (E. A. O.) 6Department of Geology & Geophysics, Texas A&M University, College Station, TX 77843 Search for other works by this author on: GSW Google Scholar Patrick J. Lynett; Patrick J. Lynett Department of Earth and Planetary Sciences Northwestern University Evanston, Illinois 60208 U.S.A. emile@earth.northwestern.edu (E. A. O.) 7Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843 Search for other works by this author on: GSW Google Scholar Vasily V. Titov; Vasily V. Titov Department of Earth and Planetary Sciences Northwestern University Evanston, Illinois 60208 U.S.A. emile@earth.northwestern.edu (E. A. O.) 8Pacific Marine Environmental Laboratories, NOAA, 7600 Sand Point Way NE, Seattle, WA 98115 Search for other works by this author on: GSW Google Scholar Spyros Foteinis; Spyros Foteinis Department of Earth and Planetary Sciences Northwestern University Evanston, Illinois 60208 U.S.A. emile@earth.northwestern.edu (E. A. O.) 4Department of Environmental Engineering, Technical University of Crete, 73100 Chania, Greece Search for other works by this author on: GSW Google Scholar Bruce E. Jaffe; Bruce E. Jaffe Department of Earth and Planetary Sciences Northwestern University Evanston, Illinois 60208 U.S.A. emile@earth.northwestern.edu (E. A. O.) 9USGS Pacific Science Center, 400 Natural Bridges Drive, Santa Cruz, CA 95060 Search for other works by this author on: GSW Google Scholar Philip L.-F. Liu; Philip L.-F. Liu Department of Earth and Planetary Sciences Northwestern University Evanston, Illinois 60208 U.S.A. emile@earth.northwestern.edu (E. A. O.) 10School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853 Search for other works by this author on: GSW Google Scholar I-chi Chan I-chi Chan Department of Earth and Planetary Sciences Northwestern University Evanston, Illinois 60208 U.S.A. emile@earth.northwestern.edu (E. A. O.) 10School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853 Search for other works by this author on: GSW Google Scholar Seismological Research Letters (2010) 81 (4): 577–591. https://doi.org/10.1785/gssrl.81.4.577 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Emile A. Okal, Hermann M. Fritz, Costas E. Synolakis, José C. Borrero, Robert Weiss, Patrick J. Lynett, Vasily V. Titov, Spyros Foteinis, Bruce E. Jaffe, Philip L.-F. Liu, I-chi Chan; Field Survey of the Samoa Tsunami of 29 September 2009. Seismological Research Letters 2010;; 81 (4): 577–591. doi: https://doi.org/10.1785/gssrl.81.4.577 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search On 29 September 2009, a strong earthquake took place south of the Samoa Islands in the southcentral Pacific. It triggered a local tsunami, which caused considerable damage and 189 fatalities on the Samoa Islands and in the northern Tonga archipelago. We present here the results of a tsunami survey conducted by an International Tsunami Survey Team in the Samoa Islands on 4-10 October 2009 and in northern Tonga on 25–27 November 2009. The earthquake occurred at 17:48:10 GMT (local time 06:48 on the 29th in Samoa; on the 30th in Tonga), with a source located at 15.51°S and 172.03°W and... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Extreme runup from the 17 July 2006 Java tsunami

The 17 July 2006 magnitude Mw 7.8 earthquake off the south coast of western Java, Indonesia, generated a tsunami that effected over 300 km of coastline and killed more than 600 people, with locally focused runup heights exceeding 20 m. This slow earthquake was hardly felt on Java, and wind waves breaking masked any preceding withdrawal of the water from the shoreline, making this tsunami difficult to detect before impact. An International Tsunami Survey Team was deployed within one week and the investigation covered more than 600 km of coastline. Measured tsunami heights and run‐up distributions were uniform at 5 to 7 m along 200 km of coast; however there was a pronounced peak on the south coast of Nusa Kambangan, where the tsunami impact carved a sharp trimline in a forest at elevations up to 21 m and 1 km inland. Local flow depth exceeded 8 m along the elevated coastal plain between the beach and the hill slope. We infer that the focused tsunami and runup heights on the island suggest a possible local submarine slump or mass movement.

Northwest Sumatra and Offshore Islands Field Survey after the December 2004 Indian Ocean Tsunami

An International Tsunami Survey Team (ITST) conducted field surveys of tsunami effects on the west coast of northern and central Sumatra and offshore islands 3–4 months after the 26 December 2004 tsunami. The study sites spanned 800 km of coastline from Breuh Island north of Banda Aceh to the Batu Islands, and included 22 sites in Aceh province in Sumatra and on Simeulue Island, Nias Island, the Banyak Islands, and the Batu Islands. Tsunami runup, elevation, flow depth, inundation distance, sedimentary characteristics of deposits, near-shore bathymetry, and vertical land movement (subsidence and uplift) were studied. The maximum tsunami elevations were greater than 16 m, and the maximum tsunami flow depths were greater than 13 m at all sites studied along 135 km of coastline in northwestern Sumatra. Tsunami flow depths were as much as 10 m at 1,500 m inland. Extensive tsunami deposits, primarily composed of sand and typically 5–20 cm thick, were observed in northwestern Sumatra.

Sri Lanka Field Survey after the December 2004 Indian Ocean Tsunami

An International Tsunami Survey Team (ITST) consisting of scientists from the United States, New Zealand, and Sri Lanka evaluated the impacts of the 26 December 2004 transoceanic tsunami in Sri Lanka two weeks after the event. Tsunami runup height, inundation distance, morphological changes, and sedimentary characteristics of deposits were recorded and analyzed along the southwest and east coasts of the country. Preliminary results show how local topography and bathymetry controlled the limits of inundation and associated damage to the infrastructure. The largest wave height of 8.71 m was recorded at Nonagama, while the greatest inundation distance of 390 m and runup height of 12.50 m was at Yala. At some sites, human alterations to the landscape increased the damage caused by the tsunami; this was particularly evident in areas of coral poaching and of sand dune removal.

Survey of the December 26th 2004 Indian Ocean tsunami in Sri Lanka

An International Tsunami Survey Team (ITST) consisting of scientists from the U.S., New Zealand, and Sri Lanka evaluated the impacts of the December 26th 2004 transoceanic tsunami in Sri Lanka two weeks after the event. Tsunami runup, height, inundation distance, morphological changes, and sedimentary characteristics of deposits were recorded and analyzed along the southwest and east coasts of the country. Preliminary results show how local topography and bathymetry controlled the limits of inundation and associated damage to the infrastructure. At some sites, human alterations to the landscape increased damage caused by the tsunami.

Field Survey of Northern Sumatra and Banda Aceh, Indonesia after the Tsunami and Earthquake of 26 December 2004

On Sunday, 26 December 2004, at 00:58 UTC (07:58 local at the epicenter), a great earthquake occurred 250 km south-west of Banda Aceh in northern Sumatra, Indonesia. With a moment magnitude of 9.0 or possibly greater (Stein and Okal, 2005), it was one of the largest instrumentally recorded earthquakes in history. The earthquake generated a large tsunami that caused extreme inundation and destruction along the northern and western coasts of Sumatra, as seen in the cities of Banda Aceh and Meulaboh. Within hours the tsunami devastated the distant shores of Thailand to the east as well as those of Sri Lanka, India, and the Maldives to the west. The tsunami also caused deaths and destruction in Somalia and other nations of east Africa and was recorded on tidal stations throughout the oceans of the world. Figure 1. Location map showing survey sites. A representative value for the maximum wave height or run-up at each location is given. The rapid response of an International Tsunami Survey Team (ITST) to the Banda Aceh, Sumatra region after the 26 December 2004 earthquake and tsunami led to the recovery of important data on the characteristics of the tsunami inundation. These data are used in conjunction with satellite imagery obtained before and shortly after the earthquake to describe the effects of the tsunami and earthquake in terms of run-up height, inundation distance, flow depth, levels of structural damage, shoreline erosion, and earthquake-related subsidence. Field data collected in Banda Aceh and nearby areas include profiles to determine run-up heights, GPS-located photographs of flow depth marks, and traces indicating flow direction. Additional information on wave arrival and behavior was collected through interviews with witnesses and survivors and from video taken during the tsunami attack. As a member of the International Tsunami Survey Team (ITST), I entered the Aceh region …

Observations by the International Tsunami Survey Team in Sri Lanka

In response to the 26 December 2004 tsunami, a survey team of scientists was dispatched to Sri Lanka. Measurements made by the team show that the tsunami elevation and runup ranged from 5 to 12 meters. Eyewitnesses report that up to three separate waves attacked the coast, with the second or third generally the largest. Our conclusion stresses the importance of education: Residents with a basic knowledge of tsunamis, as well as an understanding of how environmental modifications will affect overland flow, are paramount to saving lives and minimizing tsunami destruction.

Field Survey of the 2004 Off-Sumatra Earthquake Tsunami around the Banda Aceh, Northern Sumatra, Indonesia

The 2004 off-Sumatra earthquake (Mw=9.0) was the largest subduction-zone earthquake in the world since the 1964 Alaska earthquake. The 2004 earthquake generated large tsunamis, which propagated across the Indian Ocean and caused the catastrophic disaster. Our international tsunami survey team investigated in the province of Nanggroe Aceh Darussalam, northern Indonesia, in order to clarify the magnitude of tsunami and distribution of tsunami deposits caused by this earthquake.

Origin of the 17 July 1998 Papua New Guinea Tsunami: Earthquake or Landslide

The tsunami that struck Papua New Guinea on 17 July 1998 shortly after a Mw 7.0 earthquake (Figure 1) was one of the deadliest tsunamis in this century. At least 2,200 people died from this event, essentially destroying an entire generation in some communities. In the months following the tsunami, several international survey teams collected data in an attempt to better understand the cause of this event. Elevations of waterline marks and displaced debris measured by the first International Tsunami Survey Team (ITST; Kawata et al., 1999) indicated an average runup of 10 m occurring over a 25 km length of coastline in the vicinity of Sissano Lagoon (Figure 2). The maximum runup from this event was approximately 15 m. Tsunami runup heights of this size are commonly associated either with earthquakes of much larger magnitude or with “tsunami earthquakes” as defined by Kanamori (1972) and later discussed by Kanamori and Kikuchi (1993). Even for tsunami earthquakes, however, runup heights of 10-15 m seem only to occur for earthquakes Mw > 7.5. Because these runup heights appear anomalously high for a M 7 earthquake, other sources have been postulated for the tsunami, including a submarine landslide or mass flow. Earlier this year, the bathymetry north of Papua New Guinea was surveyed by the Japan Marine Science and Technology Center (JAMSTEC) and the South Pacific Applied Geoscience Commission (SOPAC). In a report describing the preliminary results from these cruises (Tappin et al. , 1999), bathymetric images are presented that show evidence both of a 40-km-long fault scarp and of collapse features within an approximately 10-km-wide bathymetric amphitheater (Figure 2). The report suggests that a landslide was the sole cause for the tsunami. In this paper, I revisit the common assumption that local tsunami runup scales directly with moment magnitude …

Gas, fire, and water

From the detailed report of the International Tsunami Survey Team (ITST) (Eos, March 2, 1999), it seems that we now can add two more hazards to tsunami events [Kawata et al., 1999]: the release of toxic gases and the ignition and combustion of flammable gases.This conclusion can be drawn from the investigation of last July's Papua New Guinea tsunami disaster: “The team also tried to explain reports of sea bubbling, foul smelling gas, and warm water stinging the eyes.” Among the questions and observations of the local people were “eyewitness descriptions of the tsunami as an ”infernal wall of water with fire sparkles flying.“The inferred conclusion, that the tsunami involved an underwater source of fire, would also be suggested by severe burns widely observed on the dead.” [Kawata et al, 1999].

Tsunami in Papua New Guinea was as intense as first thought

Last July's tsunami in Papua New Guinea was as intense and catastrophic as news reports indicated, a scientific survey has found, and recommendations have been put forth to avert such a disaster in the future. The tsunami and the earthquake that generated it occurred July 17, 1998, and the International Tsunami Survey Team (ITST) began a weeklong investigation July 31. It was the ninth major tsunami and the most devastating the team has studied in the past 6 years. The team was able to precisely map the inundation and determine that media reports of extreme flows to fairly small sections of shoreline were accurate. Wave heights of 10 m were confirmed along a 25‐km stretch of coastline with maximum heights of 15 m and overland flow velocities of 15–20 m/s. Both are extreme measurements, given the moderate size of the earthquake and its aftershocks.The team noted that the force of a tsunami current on an object is roughly 1000 times that of a wind of the same speed.

Daily and seasonal sea-level oscillations on the Pacific coast of Canada : Waldichuk Michael, 1964. In: Studies on Oceanography dedicated to Professor Hidaka in Commemoration of his Sixtieth Birthday, 181–201

An Mw ≈ 8.1 earthquake south of the Samoan Islands on 29 September 2009 generated a tsunami that killed 189 people. From 4 to 11 October, an International Tsunami Survey Team surveyed the seven major islands of the Samoan archipelago. The team measured locally focused runup heights of 17 m at Poloa and inundation of more than 500 m at Pago Pago. A follow-up expedition from 23 to 28 November surveying the three main islands of Tonga's northernmost Niua group revealed surprising 22 m runup and 1 km inundation. We analyze the extreme tsunami runup and complex impact distribution based on physical and societal observations combined with numerical modeling. That an outer rise/outer trench slope (OR/OTS) event is responsible for a tsunami disaster in the Pacific calls for care in identifying and defining tsunami hazards. Evacuation exercises conducted in Samoa in the preceding year may have limited the human toll; however, cars were identified as potential death traps during tsunami evacuations. This event highlights the extreme hazards from near source tsunamis when the earthquake's shaking constitutes the de facto warning, and further underscores the importance of community based education and awareness programs as essential in saving lives.

Some characteristics of 25-cps. shallow-water ambient noise : Willis Jack and F.T. Dietz, 1965. J. acoust. Soc., Am., 37 (1): 125–130

An Mw ≈ 8.1 earthquake south of the Samoan Islands on 29 September 2009 generated a tsunami that killed 189 people. From 4 to 11 October, an International Tsunami Survey Team surveyed the seven major islands of the Samoan archipelago. The team measured locally focused runup heights of 17 m at Poloa and inundation of more than 500 m at Pago Pago. A follow-up expedition from 23 to 28 November surveying the three main islands of Tonga's northernmost Niua group revealed surprising 22 m runup and 1 km inundation. We analyze the extreme tsunami runup and complex impact distribution based on physical and societal observations combined with numerical modeling. That an outer rise/outer trench slope (OR/OTS) event is responsible for a tsunami disaster in the Pacific calls for care in identifying and defining tsunami hazards. Evacuation exercises conducted in Samoa in the preceding year may have limited the human toll; however, cars were identified as potential death traps during tsunami evacuations. This event highlights the extreme hazards from near source tsunamis when the earthquake's shaking constitutes the de facto warning, and further underscores the importance of community based education and awareness programs as essential in saving lives.