Institute of Geography Universität zu Köln Zülpicher Str. 45 D-50674 Köln Germany Fax: +49-221-470-5124

Dr. Max Engel [email protected] , phone: +49-221-470-1562

Prof. Dr. Helmut Brückner [email protected], phone: +49-221-470-1724

Tsunami hazard assessment on based on sedi- mentary traces of prehistoric high-energy waves – Report to the Dienst Ruimtelijke Ontwikkeling en Beheer (DROB), Openbaar Lichaam Bonaire

This report builds on the research project “Key Processes in the Holocene Evolution of Tropical Coasts – Evaluating the Role of Hurricanes and Tsunamis” funded by the German Research Foundation (DFG) Ref.-Nos.: BR 877/26-1, RA 383/17-1, SCHA 472/10-1, SCHE 676/8-1

June 2012 Foreword This report is based on the on the research project “Key Processes in the Holocene Evolu- tion of Tropical Coasts – Evaluating the Role of Hurricanes and Tsunamis” funded by the German Research Foundation (DFG), Ref.-Nos.: BR 877/26-1, RA 383/17-1, SCHA 472/10- 1, SCHE 676/8-1. It builds upon previous investigations on processes in- volved in the accumulation of coarse-clast deposits along the coasts of , Bonaire and Curaςao carried out by A/Prof. Dr. Anja Scheffers and Prof. Dr. Dieter Kelletat. The report aims at summarising the main conclusions gained during the current research project concerning the occurrence of tsunamis on Bonaire in prehistoric times, which are based on related sedimentary deposits. Furthermore, implications for local tsunami hazard are given as well as recommendations for coping with this hazard. We tried to strictly reduce background information to the minimum necessary. Numbers in square brackets refer to more specific literature and cited references. Essential support for this research was provided by Dienst Ruimtelijke Ontwikkeling en Be- heer (DROB), Openbaar Lichaam Bonaire, in particular by Mr. Frank van Slobbe, as well as Stichting Nationale Parken (STINAPA), represented by Mrs. Elsmarie Beukenboom, Mr. Fer- nando Simal and Mr. Ramon de Leon. Furthermore, the following persons have supported and contributed to this project (in alphabetical order): Prof. Dr. Michael Amler, Dr. Andreas Bolten, Drs. Jan Brouwer, Dr. Gerhard Daut, PD Dr. Peter Frenzel, Mr. Sascha Fürstenberg, Mr. Andreas Ginau, Dr. S. Matthias May, Prof. Dr. Dieter Kelletat, Mrs. Anna M. Knopczak, Mrs. Karoline Meßenzehl, Mr. Ingo Middelhaufe, Prof. Dr. Frank Schäbitz, A/Prof. Dr. Anja Scheffers, Dr. Sander Scheffers, Prof. Dr. Andreas Vött, Dr. Volker Wennrich, Dr. Michael Wille, Mr. Timo Willershäuser. In case of questions concerning the research and implications for tsunami hazard on Bon- aire, as well as for possible future tasks, please do not hesitate to contact the authors.

1 Table of content

Introduction ...... 3 How tsunamis are triggered...... 3 Characteristics of tsunamis ...... 3 Historical tsunamis on Bonaire ...... 4 The research project ...... 5 Evidence from fine-grained sediments ...... 5 Evidence from large boulders ...... 5 Coping with uncertainties in sediment interpretation ...... 6 Coastal changes due to high energy wave impact...... 6 Dating the events ...... 7 Tsunami hazard on Bonaire ...... 8 The Caribbean Tsunami Warning System ...... 8 Recommendations for Bonaire ...... 9 References ...... 12 Authors’ publications on geologic evidence of tsunamis… ...... 13 Authors’ lectures, talks and posters… ...... 14

2 Introduction

The Caribbean region is highly vulnerable* to coastal hazards since a relatively high per- centage of the population lives right at the coast. Tourism, a major economic factor on many islands, is concentrated in coastal areas as well. The “traditional” hazards along the coasts of the Caribbean, as perceived some decades ago, are earthquakes, volcanism and storm surges during hurricanes. This focus is justified in the light of the devastating earthquake of Haiti in 2010, which represents a regional maximum in magnitude with a death toll of more than 230,000. The eruption of Mount Pelée on Martinique, which destroyed St. Pierre, the former principal town of the island, and killed around 28,000 inhabitants, and the Great Hurri- cane of 1780 with a similar number of fatalities along the Antilles island arc were outstanding disasters in terms of magnitude. Moreover, the frequency during the 500 years of historical documentation is high as well. However, history tells that the Caribbean is also prone to the risk of tsunamis. One hundred twenty-seven possible tsunamis were documented during the last 500 years, of which 53 were finally considered to be real tsunamis [5].

How tsunamis are triggered This risk is related to well-known geophysical mechanisms, which are capable of triggering tsunamis: . a sudden vertical movement of the ocean floor, mostly during submarine earthquakes at tectonic plate boundaries; . a submarine landslide at the steep continental margins; . a coastal landslide into the sea; . explosive volcanism, e.g. triggered by lava flows entering the sea; . flank collapse of volcano edifices; . a meteorite impact. All of these mechanisms occur in the Caribbean region (see Tab. 1). However, also teletsu- namis (also called: far-field tsunamis) generated in the open Atlantic Ocean threaten the Car- ibbean coasts. Worldwide devastating events of the last decade, such as the Indian Ocean Tsunami in 2004 (IOT), the Chilean Tsunami in 2010, or the Tohoku-oki Tsunami of Japan in 2011, not only stimulated research in all branches of tsunami science, but also led to an in- crease in media coverage, public awareness, community preparedness, and early warning technology [e.g. 6-7]. However, in the Caribbean there is still a lack of information regarding long-term occurrence patterns of high-magnitude tsunamis [8].

Characteristics of tsunamis Tsunamis (Japanese term for “harbour waves”) have wave lengths of up to hundreds of kilo- metres (storm waves: hundreds of metres) and heights of just a few centimetres to decime-

* Vulnerability may be defined as “the characteristics of a person or group in their situation that influence their capacity to anticipate, cope with, resist and recover from the impact of a natural hazard” [1]. Cutter [2] adds the “vulnerability as hazard of place” to the concept, which includes the physical environment, the central element of the research reported here. Another term often referred to in this context is tsunami hazard as one particular form of coastal hazards, which are understood as “physical phenomena that expose the coastal zone to risk of property damage, loss of life, or environmental degradation” [3]. In contrast, the term risk is defined “as the product of the probability of occurrence of a particular geophysical event and expected losses” [4].

3 tres in the open ocean. They reach velocities of 700-800 km/h in deep ocean waters, which is similar to the one of long-distance airplanes. Approaching the shallow waters near the coast, a tsunami reduces its speed while its height increases. Coastal inundation occurs in the form of a temporary sea level rise by the shoreward moving of a broad sheet of water or by a landward moving wall of water similar to a tidal bore [9]. Onshore flow depths of several metres and flow velocities of several metres per second are life threatening and capable to destroy all kinds of infrastructure.

Fig. 1: Simplified geological map of Bonaire. Purple symbols represent coring sites, yellow symbols indicate sites were boulder deposits were investigated. The rectangle indicates the detail map in Fig. 4.

Historical tsunamis on Bonaire Tsunamis have never been observed along the coasts of the Bonaire and the entire ABC Islands for the period of historical documentation, i.e. the last 500 years. However, this does not mean that there is no tsunami hazard on Bonaire. Major tsunamis of highest magnitude, such as the devastating events in the Indian Ocean in 2004 or in Japan in 2011, have recur- rence intervals up to 1000 years or more [10-11]. In absence of historical accounts, geologi-

4 cal deposits remain as indicators that tsunamis have occurred on Bonaire in prehistoric times.

The research project The research on which this report is based on is compiled in a PhD thesis of Max Engel, submitted to and accepted by the Faculty of Mathematics and Natural Sciences, Universität zu Köln. Free access is provided via ______. In addition, several sci- entific papers have been published. Please note that in all presentations (scientific papers, oral communications, lectures) related to the scientific investigations, the authorities of Bon- aire are explicitly acknowledged for having granted the permit for our research on Bonaire.

Evidence from fine-grained sediments In our research we used the sediments stored in bokas, narrow floodplains and mangrove swamps, (i) to identify overwash deposits related to prehistoric high-energy wave events, (ii) to differentiate between sediments laid down by hurricanes and tsunamis, and (iii) estimate the age of these deposits using physical methods. A total of 45 sediment cores (max. depth 11 m) was taken from all around the island (Lagun, Boka Washikemba, Lac Baai, Saliña Tam, Klein Bonaire, Boka Funchi, Wayaka, Boka Bartol, Playa Grandi) (Fig. 1). Cores from the most promising locations were investigated in terms of sedimentology, geochemistry, mineralogy and faunal remains. These data (e.g. Fig. 2) are valuable for subsequent tasks or analyses, such as probabilistic tsunami hazard assessment. Prehistoric tsunami deposits have the ability to extend short historical records and may provide recurrence rates for major earthquake-generated tsunamis [12]. Furthermore, we investigated whether tsunamis had transported the large boulders and blocks which are mainly distributed in the Spelonk area and the NNE-exposed coast, e.g. at Boka Olivia (Figs. ).

Fig. 2: Possible tsunami deposit (Unit II) found in a sediment core at a depth of 6.68-6.86 m below surface at Boka Bartol (Fig. 1) with the description of its characteristics. It was dated to 3300-3000 years before present.

Evidence from large boulders The largest coastal blocks and boulders (Figs. 3-4) were studied as evidence for the occur- rence of more powerful waves than those of strong tropical cyclones (locally known as hurri- canes) (Figs. 5-6). We used a mathematical model of boulder transport by waves which en- ables the calculation of minimum storm wave and tsunami heights required to move a boul- der of certain dimensions and weight. Calculated minimum storm wave heights required to quarry and move the largest blocks of Spelonk and Boka Olivia were up to three times higher

5 than those observed during recent high-category hurricanes such as Ivan in 2004 (category 5, the highest on the Saffir-Simpson Hurricane scale). Thus, little doubt remains that one or more major tsunamis have occurred within the last 5000 years.

Fig. 3: The Spelonk boulder field viewed Fig. 4: Boulder at the Spelonk boulder field from the lighthouse. likely dislocated by a tsunami.

Fig. 5: Wave approach during Hurricane Fig. 6: Flooding of the limestone terrace at Ivan 2004 at Boka Onima, Bonaire [13]. Boka Onima during Hurricane Ivan 2004 [13].

Coping with uncertainties in sediment interpretation Tsunami occurrence on Bonaire was also inferred based on overwash deposits buried in the bokas and saliñas. These sediment layers share a high number of characteristic features which are found in the deposits of modern tsunamis worldwide. Uncertainties in sediment interpretation, associated with the fact that most of these characteristic features may occur in storm deposits as well, were reduced according to (i) the results from the numerical boulder study (see above), (ii) the high tsunami potential of the southern Caribbean (several potential tsunami trigger mechanisms), (iii) the identification of sediment source areas which are out of reach for storm waves, and (iv) the lack of littoral and marine sand/mud input during recent high-category hurricanes (e.g. Hurricane Ivan 2004, 2008).

Coastal changes due to high energy wave impact The sediments of several investigated sites reflect long-lasting environmental change subse- quent to palaeotsunami impact. At the open embayment of Lagun, this is confirmed by pollen analysis. Pollen grains found in sediments beneath the candidate tsunami deposit are domi-

6 nated by mangrove types, whereas a significantly lower percentage of mangrove pollen was detected in the overlying sediment unit. Mangroves seem to have only gradually recovered from the impact; it probably took them at least several hundred years to recover. In contrast to Lagun, the bokas and saliñas of Bonaire are cut off from the sea by a barrier of coral rub- ble. The candidate tsunami deposit of Boka Bartol is vertically confined by mangrove peat and mangrove oyster shells (below) and mud containing salt and gypsum crystals (above). This pattern is interpreted as the transformation of a mangrove-fringed embayment (pre- tsunami) which requires open access to the sea into a lagoon (post-tsunami) with high salin- ity due to the establishment or closure of the barrier of coral material during the tsunami. The high amount of gypsum and halite crystals and thin layers of inorganic carbonate are the re- sult of limited water input and high evaporation rates during the dry season similar to today’s conditions. The absence of shell remains also indicates very limited exchange with the ocean.

Fig. 7: Ages of potential tsunami deposits as identified in sediment cores from different sites along the coast of Bonaire. Horizontal bars indicate the posibble time window of occurrence. Four major tsunamis were inferred for the last 4000 years. Two extreme wave events – EWE II, between 3300-3000 years before present and EWE XII 2000-1700 years before present – are well documented and left overwash deposits at various sites. The other two events (indi- cated by question marks) have a lower probability of occurrence. Radiometric ages of the coarse-clast record of Bonaire are also shown (black star) [14], though these ages do not point to certain events. Study sites are indicated in Fig. 1.

Dating the events Dating the candidate tsunami deposits buried in the sediment archives along the coast by radiocarbon (14C-AMS) leads to a chronology of potential prehistoric tsunamis on Bonaire (Fig. 7). The chronology starts with extreme wave event I (EWE I) around 3600 years ago, represented by a carbonate sand deposit bracketed by mangrove peat, which was found on Klein Bonaire. A well-preserved candidate tsunami deposit from Boka Bartol with a maximum age of 3300 years (EWE II) has counterparts on the leeward coast (Klein Bonaire, Saliña Tam, possibly between Saliña Tam and Punt’i Wekua) and the windward coast (Playa Grandi, possibly Boka Washikemba). EWE II can be identified as the best-documented pre- historic tsunami on Bonaire: EWE XII, with a maximum age of 2000 years, left massive shell- dominated deposits at Lagun (windward side) and carbonate sands at Saliña Tam, both of

7 which were interpreted as representatives of a tsunami. Deposits of another younger, un- specified EWE XVI (500 years or older) were found between Saliña Tam and Punt’i Wekua, and Boka Washikemba. Based on these results, a preliminary estimation of the recurrence interval of high-energy wave events on Bonaire, which reveal magnitudes significantly ex- ceeding those of recent high-category hurricanes and which are therefore likely to be major tsunamis, is in the order of roughly 1000 years or less. This study corroborates conclusions of predecessor studies that the hazard of tsunami does exist on Bonaire [14-18], although historical accounts on tsunami occurrence are lacking [5].

Tsunami hazard on Bonaire Since we found geological traces of potential tsunamis at almost all sites investigated along the coast of Bonaire, we consider the entire coastline to be prone to tsunami hazard. Along the windward coast, the largest boulders point to the occurrence of tsunami wave heights in the order of 8-10 m. This height estimate is similar to tsunami wave heights observed at the Venezuelan coast in historical times, e.g. at Paria in 1530 or at Puerto Tuy in 1900 [5]. The minimum inundation of such a tsunami on the carbonate platform along the windward side would be 300 m, possibly even more than 500 m. However, findings of candidate tsunami deposits in the sediment cores of the bays, bokas and saliñas, such as Boka Bartol, Saliña Tam or Lagun far inland indicate that especially these low-lying areas provide pathways for inundation and destruction by a tsunami. Thus, a low topography, as found on the entire southern part of Bonaire, is more prone to tsunami inundation. Along the leeward coast of Bonaire, low-lying residential areas – in particular those of Bel- nem, Kralendijk (Playa) or Hato, the hotel zone north of Harbour Village and industrial infra- structure such as the Cargill salt works or BOPEC located directly along the seafront – are highly vulnerable to tsunami hazard (Fig. 8). However, in case of a major tsunami, also areas more inland such as Tera Kora, Nikiboko or Sabana are at risk. Coastal overwash deposits buried in the saliña of Nort Saliña, inland of Harbour Village, are a definite proof that the sea- front is threatened by extreme waves significantly stronger than those of recent category 5 hurricanes. Nevertheless, this applies also to lower parts of the residential areas of Antriol and Nort Saliña including the commercial and administrative buildings along Amsterdamweg. O’Loughlin and Lander state in their book “Caribbean Tsunamis – A 500-Year History from 1498-1998” [5]: “A catastrophic tsunami will strike the Caribbean. It is only a matter of time.” The time of this major tsunami – which did have predecessors based on the geological traces on Bonaire and which is likely to have an impact on the island in the future – is unfor- tunately unpredictable. It may happen within the next few years or the next 500 years. How- ever, the recurrence rates deduced from our research (Fig. 3) indicate that Bonaire should be prepared right at this moment.

The Caribbean Tsunami Warning System The Caribbean special municipalities of the Netherlands, including Bonaire, are organised within the “Tsunami and Other Coastal Hazards Warning System for the Caribbean and Ad- jacent Regions” (CARIBE EWS), which is a first effort in tsunami preparedness. CARIBE EWS was installed in 2005 by the UNESCO Intergovernmental Oceanographic Commission (IOC). It was founded in order to provide assistance on tsunami risk mitigation to member states in the Caribbean region. Progress of CARIBE EWS is reported during annual meet- ings. In 2010, the National Oceanic and Atmospheric Administration (NOAA) of the USA es- tablished the Caribbean Tsunami Warning Program, located at Mayagüez, , and

8 endorsed by CARIBE EWS, as an initial step towards a proper Caribbean Tsunami Warning Center (CTWC). The program gathers information on tsunami travel times in the Caribbean and provides real-time earthquake data by the United States Geological Survey (USGS). Thus far, tsunami alerts for the Caribbean are still issued by NOAA West Coast and Alaska Tsunami Warning Center (NWS WCATWC) in Alaska for Puerto Rico and the US and British Virgin Islands, as well as NOAA National Weather Service Pacific Tsunami Warning Center (NWS PTWC) on Hawaii for the rest of the Caribbean including Bonaire. Improvements of CARIBE EWS are highly mandatory, in particular regarding com- munication [19-20].

Fig. 8: Detail of the official topographic map of Bonaire (1:25,000) and the digital elevation model based on low-resolution SRTM (90 m resolution). The map shows the highly vulner- able coastal area of Kralendijk up to Hato as well as Sabana, Nikiboko and Tera Kora. Nort Saliña and Antriol are located on higher grounds, but still are vulnerable. Yellow colours iden- tify tsunami safe areas even for the worst case scenarios Lightest green areas surrounding the yellow colours are also likely to represent tsunami safe areas.

Recommendations for Bonaire The Meteorological Department of Curaçao on the sister island of Bonaire recently imple- mented a working group which developed a document communicating local tsunami hazard assessment [21] and local risk analysis [22] in order to raise public awareness and stimulate local tsunami education. Palaeotsunami research of Anja Scheffers [15-16] was considered for the evaluation of the local tsunami hazard (see bibliography in [21]). The risk analysis

9 provides a definition of areas of high risk for lives and infrastructure. A similar approach is highly recommended for Bonaire. Where a tsunami hazard is identified, community preparedness has to be increased and knowledge about tsunamis should be fostered. As indicated by IOC-UNESCO, key efforts include measures of urban planning (zoning restrictions, relocation to higher grounds, estab- lishing evacuation routes and zones) and community education. A high degree of prepared- ness is required especially in the case of near-field tsunamis with short travel times (see Tab. 1). Scenarios of the largest hypothetical tsunamis based on regional geophysical conditions and long-term recurrence rates according to geological data (such as those from the re- search project which this report is based on) should be considered in order to support maxi- mum safety [23].

Tab. 1: A selection of trigger mechanisms for tsunamis potentially threatening Bonaire, along with travel times and historical examples. Data are taken from [21, 24-33].

Triggering area Tsunami travel time Mechanism Historical example to Bonaire in case of highest magnitudes

Mona Passage (CP-NAP bound- 1-1.5 hrs Earthquake due to normal faulting 11 Oct 1918, Mw = 7.3 ary)

SW Portuguese continental mar- >8 hrs Earthquake due to an active thrust 1 Nov 1755, Mw = 8.5 ± gin fault? 0.3

Cumbre Vieja Volcano, Canary >6 hrs Landslide due to failure of the ? Islands western flank of the volcano

El Pilar Fault Zone, <30 min Earthquake due to a rupture of an 1 Sep 1530 offshore section of the El Pilar fault

Lesser Antilles arc 1.5-2 hrs Earthquake due to subduction of a 7 May 1842 segment between and Guadeloupe

Kick ‘em Jenny Volcano, Grenada 1-1.5 hrs Explosive submarine volcanic activ- 24 July 1939, then 10 ity times between 1939- 1994

Anegada Passage, Virgin Islands 1-1.5 hrs Earthquake due to strike-slip faulting 18 Nov 1867, Mw = 7.5

Mt. Soufriere, 1-1.5 hrs Lava dome collapse, pyroclastic 20 May 2006 flows entering the sea

Hispaniola (Enriquillo or Septen- 1-1.5 hrs Earthquake due to strike-slip fault 12 Jan 2010, Mw = 7.0 trional Faults)

 In order to prepare more precise and site-specific countermeasures, we recommend to conduct: i. A follow-up study aiming at modelling tsunamis based on possible trigger mecha- nisms listed in Tab. 1, which fit the extent of tsunami sediments identified in the cur- rent study. Coastal inundation based on such models represents a solid basis for tsu- nami hazard maps. Since the tsunami sediments cover more than 4000 years, they

10 provide much more reliable evidence for the highest magnitude of tsunamis than the short historical record. ii. A survey of coastal land use and an assessment of tsunami vulnerability (people and property) in a high spatial resolution on a single-building scale. iii. An analysis of the coastal geomorphology and inland topography, as well as offshore bathymetry is urgent for determining pathways of tsunami inundation and the design of evacuation routes. iv. An evaluation of the awareness and preparedness of local residents in terms of tsu- namis. Organisation of public education events, i.e. communicate how to behave in case of a tsunami alert. Take tsunami education into the schools! v. Planning of evacuation routes and tsunami safe places on higher grounds. vi. Marine flood protection of coral boulder landforms: structures along the coast which may damp the effects of tsunami inundation are the natural ridges and ramparts of coral rubble. These landforms were created over thousands of years by high-energy wave events. At least, during Hurricane Ivan in 2004, waves did not cross these bar- riers. These landforms provide invaluable geological archives for prehistoric coastal evolution and extreme wave events as shown by several researchers, including the study which this report is based on. Unfortunately, these landforms are heavily being mined for construction purposes and only a fraction of their original extent is pre- served.

Cologne (Köln), 12 June 2012

Dr. Max Engel Prof. Dr. Helmut Brückner

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12 [21] Meteorological Service Netherlands Antilles and Aruba, 2010a. Beoordeling Tsunami Gevaar voor het Eilandgebied Curaçao – Deel I: “Tsunami Hazard Assessment”. http://www.meteo.an/include/Pub/documents/TSU%20_final.pdf. [22] Meteorological Service Netherlands Antilles and Aruba, 2010b. Beoordeling Tsunami Gevaar voor het Eilandgebied Curaçao – Deel II: “Risicoanalyse”. http://www.meteo.an/include/Pub/documents/RA_final.pdf. [23] IOC (Intergovernmental Oceanographic Commission), 2008. Tsunami preparedness – Information guide for disaster planners. Intergovernmental Oceanographic Commission Manuals and Guides 49. http://www.ioc- tsunami.org/images/stories/documents/manualandguides49_e.pdf. [24] Smith, M.S., Sheperd, J.B., 1995. Potential Cauchy-Poisson Waves Generated by Submarine Eruptions of Kick 'em Jenny Volcano. Natural Hazards 11, 75-94. [25] Ward, S.N., Day, S., 2001. Cumbre Vieja Volcano – potential collapse and tsunami at La Palma, Canary Islands. Geophysical Research Letters 28, 3397-4000. [26] Zahibo, N., Pelinovsky, E.N., 2001. Evaluation of tsunami risk in the Lesser Antilles. Natural Hazards and Earth System Sciences 1, 221-231. [27] Zahibo, N., Pelinovsky, E., Yalciner, A., Kurkin, A., Koselkov, A., Zaitsev, A., 2003. The 1867 Virgin Island tsunami: observations and modelling. Oceanologica Acta 26, 609-621. [28] Audemard, F.J., 2007. Revised seismic history of the Pilar fault, northeastern Venezuela, from the Cariaco 1997 earthquake and recent preliminary paleoseismic results. Journal of Seismology 11, 311-326. [29] McHugh, C.M., Seeber, L., Braudy, N., Cormier, M.-H., Davis, M.B., Diebold, J.B., Dieudonne, N., Douilly, R., Gulick, S.P.S., Hornbach, M.J., Johnson III, H.E., Mishkin, K.R., Sorlien, C.C., Steckler, M.S., Symithe, S.J., Templeton, J., 2011. Offshore sedimentary effects of the 12 January 2010 Haiti earthquake. Geology 39, 723- 726. [30] Roger, J., Baptista, M.A., Sahal, A., Accary, F., Allgeyer, S., Hébert, H., 2011. The transoceanic 1755 Lisbon Tsunami in Martinique. Pure and Applied Geophysics 168, 1015-1031. [31] Harbitz, C.B., Glimsdal, S., Bazin, S., Zamora, N., Løvholt, F., Bungum, H., Smebye, H., Gauer, P., Kjekstad, O., 2012. Tsunami hazard in the Caribbean: Regional exposure derived from credible worst case scenarios. Con- tinental Shelf Research 38, 1-23. [32] NOAA National Geophysical Data Center, 2012. Tsunami Travel Time Maps for the Atlantic, Indian and Pacif- ic Oceans. http://www.ngdc.noaa.gov/hazard/tsu_travel_time_events.shtml#Atlantic. [33] Trofimovs, J., Foster, C., Sparks, R.S.J., Loughlin, S., Le Friant, A., Deplus, C., Porrit, L., Christopher, T., Luckett, R., Talling, P.J., Palmer, M.R., Le Bas, T., 2012. Submarine pyroclastic deposits formed during the 20th May 2006 dome collapse of the Soufrière Hills Volcano, Montserrat. Bulletin of Volcanology 74, 391-405.

Authors’ publications on geologic evidence of tsunamis on Bonaire Benner, R., Browne, T., Brückner, H., Kelletat, D., Scheffers, A., 2010. Boulder Transport by Waves: Progress in Physical Modelling. Zeitschrift für Geomorphologie N.F. 54 (Suppl. 3), 127-146. Engel, M., 2012. The chronology of prehistoric high-energy wave events (tropical cyclones, tsunamis) in the southern Caribbean and their impact on coastal geo-ecosystems – a case study from Bonaire (). PhD thesis, Faculty of Mathematics and Natural Sciences, Universität zu Köln, Germany. Engel, M., Brückner, H., 2011. The identification of palaeo-tsunami deposits - a major challenge in coastal sedi- mentary research. In: Karius, V., Hadler, H., Deicke, M., von Eynatten, H., Brückner, H., Vött, A. (eds.), Dynamische Küsten - Grundlagen, Zusammenhänge und Auswirkungen im Spiegel angewandter Küstenforschung. Proceedings of the 28th Annual Meeting of the German Working Group on Geography of Oceans and Coasts, 22-25 Apr 2010, Hallig Hooge. Coastline Reports 17, 65-80. Engel, M., May, S.M., 2012. Bonaire's boulder fields revisited: Evidence for Holocene tsunami impact on the Lee- ward Antilles. Quaternary Science Reviews, doi:10.1016/j.quascirev.2011.12.011. Engel, M., Brückner, H., Kelletat, D., Schäbitz, F., Scheffers, A., Vött, A., Wille, M., Willershäuser, T., 2008. Trac- es of Holocene extreme events within sediment traps along the coast of Bonaire (Netherlands Antilles). GI²S Coast Research Publication 6, 29-31. Engel, M., Bolten, A., Brückner, H., Daut, G., Kelletat, D., Schäbitz, F., Scheffers, A., Scheffers, S.R., Vött, A., Wille, M., Willershäuser, T., 2009. Reading the chapter of extreme wave events in nearshore geo-bio-archive of Bonaire (Netherlands Antilles) – initial results from Lagun and Boka Bartol. In: Vött, A., Brückner, H. (eds.), Er- gebnisse aktueller Küstenforschung. Beiträge der 26. Jahrestagung des Arbeitskreises „Geographie der Meere und Küsten“, 25.-27. April 2008 in Marburg. Marburger Geographische Schriften 145, 157-178.

13 Engel, M., Brückner, H., Wennrich, V., Scheffers, A., Kelletat, D., Vött, A., Schäbitz, F., Daut, G., Willershäuser, T., May, S.M., 2010. Coastal stratigraphies of eastern Bonaire (Netherlands Antilles): New insights into the palaeo-tsunami history of the southern Caribbean. Sedimentary Geology 231, 14-30. Engel, M., Brückner, H., Messenzehl, K., Frenzel, P., May, S.M., Scheffers, A., Scheffers, S., Wennrich, V., Kelletat, D., in press. Shoreline changes and high-energy wave impacts at the leeward coast of Bonaire (Nether- lands Antilles). Earth, Planets and Space. Engel, M., Brückner, H., Scheffers, A., May, S.M., Kelletat, D., in press. Holocene sea levels of Bonaire (Leeward Antilles) and tectonic implications. Zeitschrift für Geomorphologie N.F. Engel, M., Brückner, H., Fürstenberg, S., Frenzel, P., Konopczak, A.M., Scheffers, A., Kelletat, D., May, S.M., Schäbitz, F., Daut, G., in review. Prehistoric Caribbean tsunamis in coastal sedimentary archives – new data from Washington Slagbaai National Park, Bonaire (Leeward Antilles), and a tentative synthesis of published records. The Holocene. Mastronuzzi, G., Brückner, H., Sansò, P., Vött, A., eds., 2010. Tsunami fingerprints in different archives – Sedi- ments, dynamics and modelling approaches. Proceedings of the 2nd International Tsunami Field Symposium in Ostuni (Italy) and Lefkada (Greece). Zeitschrift für Geomorphologie N.F. 54 (Suppl. 3), 356 pp. Scheffers, A., Kelletat, D., Engel, M., 2009. Die Entwicklung der Tsunamiforschung nach der Katastrophe vom 26.12.2004. Geographische Rundschau 61 (12), 12-18.

Authors’ lectures (L), talks (T) and posters (P) on geologic evidence of tsunamis on Bonaire (T) 31 Aug 2012: 24th Annual Meeting of the German Working Group on Natural Hazards, Bonn: Tsunamis in the southern Caribbean – discrepancies between the historical record and geological archives (M. Engel, H. Brückner, S.M. May, A. Scheffers, P. Frenzel, S. Fürstenberg, K. Meßenzehl, A.M. Konopczak, D. Kelletat, G. Daut, V. Wennrich, F. Schäbitz, T. Willershäuser, A. Vött). (T) 26-30 Aug 2012: 32nd International Geographical Congress, Cologne: (I) Dating tsunami-induced transport of coral reef megaclasts on Bonaire (Leeward Antilles): a cosmogenic nuclide dating approach (36Cl) (G. Rixhon, H. Brückner, M. Engel, S.M. May, T. Dunai); (II) Ostracoda and Foraminifera in Coastal Research (A. Pint, P. Frenzel, H. Brückner, T. Daniel, M. Engel, S. Fürstenberg, D. Kelterbaum, H. Schneider, C. Trog). (T) 26-29 Apr 2012: 30th Annual Meeting of the German Working Group on Geography of Oceans and Coasts, Mainz: Blocks and boulders on Bonaire: What they tell us and what they don't (M. Engel, S.M. May, H. Brückner). (P) 22-27 Apr 2012: European Geoscience Union (EGU) General Assembly, Vienna: Revisiting boulder fields on Bonaire (Leeward Antilles) (M. Engel, S.M. May, H. Brückner). Geophysical Research Abstracts 14, EGU2012- 854. (T) 28 Nov - 03 Dec 2011: 2nd joint IGCP 588: ' Preparing for Coastal Change' and INQUA 1001: ' Quaternary coastal change and records of extreme marine inundation on coastal environments' meeting in Bangkok, Thai- land: Prehistoric tsunamis in the Caribbean – new data from Washington Slagbaai National Park, Bonaire, and a first tentative basinwide synthesis (M. Engel, H. Brückner, S.M. May, A. Scheffers, P. Frenzel, S. Fürstenberg, A.M. Konopczak, K. Meßenzehl, D. Kelletat, V. Wennrich, S. Scheffers, G. Daut, F. Schäbitz). (P) 21-27 Jul 2011: XVIII. INQUA-Congress Bern, Switzerland: (I) Subsurface washover deposits on Bonaire (Leeward Antilles) - tsunamis or tropical cyclones? (M. Engel, H. Brückner, P. Frenzel, V. Wennrich, A.M. Konopczak, K. Meßenzehl, T. Willershäuser, S.M. May, A. Scheffers, S. Scheffers, D. Kelletat, A. Vött, G. Daut, F. Schäbitz); (II) An enhanced empirical dataset for estimating wave-induced boulder transport at Spelonk, Bon- aire (Netherlands Antilles) (S.M. May, M. Engel, H. Brückner). (T)15 Jul 2011: Summer festival of the Geoverbund ABC/J (Universities of Aachen, Bonn and Cologne/Research Centre Jülich): Naturrisiken und Geoarchäologie - Fallbeispiele aus der Karibik und Saudi-Arabien (M. Engel). (P) 28-30 Apr 2011: 29th Annual Meeting of the German Working Group on Geography of Oceans and Coasts, Bremen: (I) Ecosystem changes as a result of extreme wave events – the example of Boka Bartol, Bonaire (Dutch Antilles) (A.M. Konopczak, M. Engel, H. Brückner, G. Daut); (II) High energy wave events as a driving factor of coastal morphodynamics – an example from leeward Bonaire (Dutch Caribbean) (K. Meßenzehl, M. Engel, H. Brückner, P. Frenzel, V. Wennrich, G. Daut). (P) 13-17 Dec 2010: AGU Fall Meeting 2010, San Francisco (USA): Palaeo-tsunami in the southern Caribbean: clarity through new geological archives? (M. Engel, H. Brückner, K. Meßenzehl, P. Frenzel, V. Wennrich, S.M. May, G. Daut, T. Willershäuser, A. Scheffers, S. Scheffers, A. Vött, D. Kelletat). Eos Transactions AGU, Fall Meeting Suppl., Abstract OS31D-1452. (T) 10-13 Oct 2010: GeoDarmstadt 2010: Coastal stratigraphies of Bonaire (Netherlands Antilles): New insights into the palaeo-tsunami history of the southern Caribbean (M. Engel, H. Brückner, K. Meßenzehl, A. Konopczak,

14 A. Scheffers, S. Scheffers, D. Kelletat, F. Schäbitz, A. Vött, T. Willershäuser, S.M. May, V. Wennrich, G. Daut, P. Frenzel). Schriftenreihe der Deutschen Gesellschaft für Geowissenschaften 68, 160-161. (L) 30 Apr 2010: International YMCA University of Applied Sciences, Kassel: Tsunami – geologische und geogra- phische Aspekte einer Naturkatastrophe (H. Brückner) (T) 22-25 Apr 2010: 28th Annual Meeting of the German Working Group on Geography of Oceans and Coasts, Hallig Hooge: The interpretation of high-energy wave deposits - recent progress and challenges (M. Engel, H. Brückner). (T) 10-16 Apr 2010: 3rd International Tsunami Field Symposium, Sendai (Japan): Current field data on pre- Columbian tsunamis in the Southern Caribbean (M. Engel, H. Brückner, D. Kelletat, A. Scheffers, A. Vött). (P) 24-26 Apr 2009: 27th Annual Meeting of the German Working Group on Geography of Oceans and Coasts, Kiel: Geomorphic change, sea level rise, and the influence of extreme wave events at Lagun (Bonaire, Nether- lands Antilles) during the Holocene (T. Willershäuser, M. Engel, G. Daut, V. Wennrich, M. Wille, H. Brückner, D. Kelletat, F. Schäbitz, A. Scheffers, S.R. Scheffers, A. Vött). (P) 19-24 Apr 2009: European Geoscience Union (EGU) General Assembly, Vienna: High-energy wave deposits at the eastern shore of Bonaire (Netherlands Antilles) (M. Engel, T. Willershäuser, A. Bolten, H. Brückner, G. Daut, V. Wennrich, D. Kelletat, S.M. May, A. Scheffers, S.R. Scheffers, F. Schäbitz, A. Vött). Geophysical Re- search Abstracts 11, EGU2009-8468. (L) 02 Feb 2009: Public lecture, CIEE Research Station Bonaire (Dutch Antilles): The coastline of Bonaire during the recent geologic past (M. Engel). (T) 21-28 Sep 2008: 2nd International Tsunami Field Symposium, Ostuni - Puglia (Italy) and Lefkada (Ionian Is- lands, Greece): Traces of Holocene extreme wave events in sediment traps along the coast of Bonaire (Nether- lands Antilles) (M. Engel, H. Brückner, D. Kelletat, F. Schäbitz, A. Scheffers, A. Vött, V. Wennrich, M. Wille, T. Willershäuser). (T) 25-27 Apr 2008: 26th Annual Meeting of the German Working Group on Geography of Oceans and Coasts, Marburg: Reading the chapter of extreme wave events in nearshore geo-bio-archives of Bonaire (Netherlands Antilles) - first results (M. Engel, H. Brückner, D. Kelletat, F. Schäbitz, A. Scheffers, A. Vött, M. Wille, T. Willershäuser). (L) 21 Jan 2008: Public lecture, CIEE Research Station Bonaire (Dutch Antilles): Bonaire in the focus of world- wide research on extreme wave events (D. Kelletat, A. Scheffers, M. Engel, F. Schäbitz).

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