Tsunami Catalogue Research Articles

Assessing enigmatic boulder deposits in NE Aegean Sea: importance of historical sources as tool to support hydrodynamic equations

Abstract. Due to their importance in the assessment of coastal hazards, several studies have focused on geomorphological and sedimentological field evidence of catastrophic wave impacts related to historical tsunami events. Among them, many authors used boulder fields as important indicators of past tsunamis, especially in the Mediterranean Sea. The aim of this study was to understand the mechanism of deposition of clusters of large boulders, consisting of beachrock slabs, which were found on the southern coasts of Lesvos Island (NE Aegean Sea). Methods to infer the origin of boulder deposits (tsunami vs. storm wave) are often based on hydrodynamic models even if different environmental complexities are difficult to be incorporated into numerical models. In this study, hydrodynamic equations did not provide unequivocal indication of the mechanism responsible for boulder deposition in the study area. Further analyses, ranging from geomorphologic to seismotectonic data, indicated a tsunami as the most likely cause of displacement of the boulders but still do not allow to totally exclude the extreme storm origin. Additional historical investigations (based on tsunami catalogues, historical photos and aged inhabitants interviews) indicated that the boulders are likely to have been deposited by the tsunami triggered by the 6.7 Ms Chios-Karaburum earthquake of 1949 or, alternatively, by minor effects of the destructive tsunami produced by 1956's Amorgos Island earthquake. Results of this study point out that, at Mediterranean scale, to flank numerical models with the huge amount of the available historical data become a crucial tool in terms of prevention policies related to catastrophic coastal events.

Applicability of the Decision Matrix of North Eastern Atlantic, Mediterranean and connected seas Tsunami Warning System to the Italian tsunamis

Abstract. After the 2004 Indian Ocean tsunami catastrophe, UNESCO through the IOC (Intergovernmental Oceanographic Commission) sponsored the establishment of Intergovernmental Coordination Groups (ICG) with the aim to devise and implement Tsunami Warning Systems (TWSs) in all the oceans exposed to tsunamis, in addition to the one already in operation in the Pacific (PTWS). In this context, since 2005, efforts have begun for the establishment of TWSs in the Indian Ocean (IOTWS), in the Caribbean area (CARIBE EWS) and in the North Eastern Atlantic, the Mediterranean and Connected Seas (NEAMTWS). In this paper, we focus on a specific tool that was first introduced in the PTWS routine operations, i.e., the Decision Matrix (DM). This is an easy-to-use table establishing a link between the main parameters of an earthquake and the possible ensuing tsunami in order to make quick decision on the type of alert bulletins that a Tsunami Warning Center launches to its recipients. In the process of implementation of a regional TWS for the NEAM area, two distinct DMs were recently proposed by the ICG/NEAMTWS, one for the Atlantic and the other for the entire Mediterranean area. This work applies the Mediterranean NEAMTWS DM to the earthquakes recorded in Italy and compares the action predicted by the DM vs. the action that should be appropriate in view of the observed tsunami characteristics with the aim to establish how good the performance of the Italian TWS will be when it uses the DM for future events. To this purpose, we make use of the parametric catalogue of the Italian earthquakes (CPTI04) compiled in 2004 and the most recent compilation of the Italian tsunami, based on the Italian Tsunami Catalogue of 2004 and the subsequent revisions. In order to better compare the TWS actions, we have identified four different kinds of action coding them from 0 to 3 according to the tsunami severity and have further considered three different distance ranges where these actions apply, that is local, regional and basin-wide, that refer to the distance of the message recipients from the tsunami source. The result of our analysis is that the actions prescribed by the DM are adequate only in 45%–55% of the cases, overestimations are about 37% and underestimations are the rest. As a whole, the predictive ability of the DM is not satisfactory, which implies that recipients have the difficult task in managing bulletins carrying a great deal of uncertainty and on the other hand also suggests that strategies to improve the DM or to go beyond the DM need to be found.

Assessing historical rate changes in global tsunami occurrence

SUMMARY The global catalogue of tsunami events is examined to determine if transient variations in tsunami rates are consistent with a Poisson process commonly assumed for tsunami hazard assessments. The primary data analyzed are tsunamis with maximum sizes >1m. The record of these tsunamis appears to be complete since approximately 1890. A secondary data set of tsunamis >0.1m is also analyzed that appears to be complete since approximately 1960. Various kernel density estimates used to determine the rate distribution with time indicate a prominent rate change in global tsunamis during the mid-1990s. Less prominent rate changes occur in the early- and mid-20th century. To determine whether these rate fluctuations are anomalous, the distribution of annual event numbers for the tsunami catalogue is compared to Poisson and negative binomial distributions, the latter of which includes the effects of temporal clustering. Compared to a Poisson distribution, the negative binomial distribution model provides a consistent fit to tsunami event numbers for the >1m data set, but the Poisson null hypothesis cannot be falsified for the shorter duration >0.1m data set. Temporal clustering of tsunami sources is also indicated by the distribution of interevent times for both data sets. Tsunami event clusters consist only of two to four events, in contrast to protracted sequences of earthquakes that make up foreshock–main shock–aftershock sequences. From past studies of seismicity, it is likely that there is a physical triggering mechanism responsible for events within the tsunami source ‘mini-clusters’. In conclusion, prominent transient rate increases in the occurrence of global tsunamis appear to be caused by temporal grouping of geographically distinct mini-clusters, in addition to the random preferential location of global M >7 earthquakes along offshore fault zones.

Historical tsunamis in the Adriatic Sea

Tsunami activity in the Adriatic Sea from the sixteenth century until the present has been analysed with the ultimate goal to improve the European tsunami catalogue and provide data for a new geo-database of tsunami events in the European-Mediterranean region. The study encompasses twenty-seven events, nine on the western and eighteen on the eastern coast of the Adriatic, with special attention being devoted to contemporary sources and to local journals and newspapers. For all the analysed events, the path of information from coeval sources, through the nineteenth century and up to modern tsunami catalogues, has been constructed. Tsunamis on the western coast have already been studied, but to obtain a coherent picture of tsunamigenic activity in the Adriatic Sea, they have been included in this work. Furthermore, the study was extended to see whether they had propagated to the opposite coast. Most of the events on the eastern coast have now been systematically analysed for the first time. The search of bibliographical sources revealed three new reports on tsunamis on the eastern coast that had not been previously recorded in international publications. The study established that, out of the eighteen eastern Adriatic events, twelve can be considered false, while six were true tsunamis. In the last 600 years, fifteen true tsunami events occurred in the Adriatic. One was very strong, six were strong or rather strong, and eight were light tsunamis. As a final result of this analysis, carried out according to standardised criteria, fifteen Adriatic tsunami events will be inserted in the TRANSFER (Tsunami Risk ANd Strategies For the European Region) database for the European-Mediterranean region.

Tsunami hazard in the Black Sea and the Azov Sea: a new tsunami catalogue

Abstract. Data on tsunamis occurring in the Black Sea and the Azov Sea from antiquity up to the present were updated, critically evaluated and compiled in the standard format developed since the 90's for the New European Tsunami Catalogue. Twenty nine events were examined but three of them, supposedly occurring in 557 AD, 815 AD and 1341 or 1343, were very likely falsely reported. Most of the remaining 26 events were generated in Crimea, offshore Bulgaria as well as offshore North Anatolia. For each of the 26 events examined, 22 events were classified as reliable ones receiving a score of 3 or 4 on a 4-grade reliability scale. Most of them were caused by earthquakes, such as the key event 544/545 of offshore Varna, but a few others were attributed either to aseismic earth slumps or to unknown causes. The tsunami intensity was estimated using the traditional 6-grade scale and the new 12-grade scale introduced by Papadopoulos and Imamura (2001). From 544/545 up to now, only two reliable events of high intensity K ≥ 7 have been reported, which very roughly indicates that the mean repeat time is ∼ 750 years. Five reliable tsunamis of moderate intensity 4 ≤ K < 7 have been observed from 1650 up to the present, which implies a recurrence of 72 years on the average. Although these calculations were based on a very small statistical sample of tsunami events, the repeat times found are consistent with the theoretical expectations from size-frequency relations. However, in the Black Sea there is no evidence of tsunamis of very high intensity (K ∼ 10) such as the AD 365, 1303 and 1956 ones associated with large earthquakes occurring along the Hellenic arc and trench, Greece, or the 1908 one in Messina strait, Italy. This observation, along with the relatively low tsunami frequency, indicates that the tsunami hazard in the Black Sea is low to moderate but not negligible. The tsunami hazard in the Azov Sea is very low because of the very low seismicity but also because of the shallow water prevailing there. In fact, only three possible tsunami events have been reported in the Azov Sea.

Revision of the tsunami catalogue affecting Turkish coasts and surrounding regions

Abstract. The coasts of Turkey have been hit by tsunamis in the past. The first national earthquake-tsunami catalogues were compiled in the early 1980s while the most up-to-date tsunami catalogues are mainly the products of recent European projects. The EU projects GITEC and GITEC-TWO (Genesis and Impact of Tsunamis on the European Coasts) and TRANSFER (Tsunami Risk ANd Strategies For the European Region) have added important contributions in establishing and developing unified criteria for tsunami parameterisation, standards for the quality of the data, the data format and the database general architecture. On the basis of these new aspects and based on recent marine geophysical data, tsunamigenic earthquakes, tsunami intensities and their reliability have been revised. The current version of the database contains 134 events, most of which have affected the Turkish coasts seriously during the last 3500 years. The reliability index of 76 events was "probable" and "definite", so that they could be used for assessment of the risk along the Turkish coastal region and for implementation of prevention policies.

TSUNAMI HAZARD IN THE EASTERN MEDITERRANEAN SEA: STRONG EARTHQUAKES AND TSUNAMIS IN THE WEST HELLENIC ARC AND TRENCH SYSTEM

The West Hellenic Arc and Trench (WHA-T) system is seismotectonically one of the most active in the European–Mediterranean region. Data on earthquake and tsunami phenomena occurring in the tectonic segment of the WHA-T from the antiquity up to the present have been updated, critically evaluated, and compiled in the standard format developed for the New European Tsunami Catalog. Most of the tsunamis documented are caused by strong earthquakes occurring in the area offshore Crete Island which is one of the most tsunamigenic areas in the entire Mediterranean Sea region. The major event of AD365 appears to be the largest ever occurred in the Mediterranean Sea at least in the last 2.5 millennia. The mean repeat time of strong tsunamis is calculated from intensity-frequency statistics and probabilistic hazard assessment is performed by assuming random temporal distribution of the events.

경험자료에 의한 동해안의 지진해일 재해도 평가

In this study, a tsunami hazard curve was determined for a probabilistic safety assessment (PSA) of a tsunami event at a Nuclear Power Plant site. A Tsunami catalogue was developed by using the historical tsunami record prior to 1900 and the instrumental tsunami record after 1900. For the evaluation of the return period of the tsunami run-up height, power-law, upper-truncated power law and exponential function were considered for the assessment of regression curves and each result was compared. Although there were in total only 9 tsunami records on the east coast of Korea during the time period of the tsunami catalogue, there is no research like this about tsunami hazard curve evaluation, so this research lays a foundation for probabilistic tsunami hazard assessment (PTHA)

Catalogue of Tsunamis in the Eastern Mediterranean from Antiquity to Present Times

This paper presents a systematic compilation of all data pertainingto tsunamis observed or recorded in the Eastern Mediterranean fromantiquity to present times (1500 b.C. to 1980 a.D.). The first cataloguehas been published by Prof. N.N. Ambraseys in the "Bulletin of theSeismological Society of America" (Vol. 52, No 4, October 1962) and thishas formed the skeleton of this paper. All of the available informationhas been compiled from historical accounts, newspaper archives, otherreports, and recent mareographic data. The earthquake data have beenextracted from the Seismological Institute of Athens and relative bibliography.Most of the events listed are associated with earthquakes, butsome are the result of volcanic activity . Many of the tsunamis havebeen generated along the coast of Greece, Albania, South Yugoslavia,Turkey, Syria and Israel. There is little doubt that the large conjugatefault system along, the west coast of Greece, Crete and Rodos till thesouth coast of Turkey is often responsible for the earthquakes in thisarea and most of tsunamis in the Eastern Mediterranean.

Tsunami Catalogs for the Eastern Mediterranean, Revisited

We critically examine tsunami catalogs for the eastern Mediterranean published in the last decade, by reference to the original sources. Such catalogs have been widely used in the aftermath of the 2004 Boxing Day tsunami for probabilistic hazard analysis, even for projections in a ten-year timeframe. We correct classification and other spurious errors and posit a new list. We conclude that, for some events, any assignment of magnitude (even on a six-point intensity scale) is inappropriate due to lack of information. Furthermore, we assert that any tsunami catalog, including ours, can only be used in conjunction with sedimentologic evidence to quantitatively infer return periods of large events. Statistical analyses correlating the numbers of tsunami events only from catalogs with inferred intensities are meaningless, at least when focusing on specific locales where only a handful of tsunamis have been historically reported. Quantitative hazard assessments based on scenario events of historic tsunamis for which—at best—only the size and approximate location of the parent earthquake is believed known should be undertaken with extreme caution and only with the benefit of geologic studies to enhance the understanding of the local tectonics.

Tsunami Hazard Assessment on the Southern Coast of Spain

In this study an indirect statistical method has been proposed to estimate the tsunami hazard assessment along the Alborán Sea Coast (Southeastern Spanish Coast). This method can be summarized as: (1) analysis of the global neotectonic setting, including geodynamic processes as well as seismicity of the region; (2) tsunami source model; (3) generation of a numerical data base of tsunami events using a numerical model; (4) probabilistic model based on Monte-Carlo simulations in order to generate a synthetic tsunami catalogue; and (5) a multidimensional interpolation method applied to combine the numerical data base with the synthetic catalogue to produce inundation maps. The purpose of this study is to establish tsunami-wave elevation at the shoreline versus the return period curves for different locations along the Alborán Sea coast. Furthermore, an inundation map of the city of Roquetas del Mar (Almeria) has been obtained. It is concluded that the tsunamis generated in the Alborán basin have a medium to low hazard, with the most important elevations in the Málaga, Adra and Melilla areas.

Current knowledge on the Central America historical seismicity: an analysisof recent catalogues

Historical seismicity studies in Central America have increased since 1980. Currently, there is a well-organized regional digital catalogue database structured according to modern techniques. It contains more than 17 000 earthquakes which occurred between 1520 and 1992. A regional tsunami catalogue is also available. The historical seismicity research included a more complete earthquake documentation obtained from foreign and Central American depositories. New intensity data point estimates and isoseismal maps allows among others, macroseismic magnitude calculations and seismogenic source determinations, for many pre-1900 earthquakes. Future trends in Central America historical seismicity research are discussed.

On the moroccan tsunami catalogue

Abstract. A primary tool for regional tsunami hazard assessment is a reliable historical and instrumental catalogue of events. Morocco by its geographical situation, with two marine sides, stretching along the Atlantic coast to the west and along the Mediterranean coast to the north, is the country of Western Africa most exposed to the risk of tsunamis. Previous information on tsunami events affecting Morocco are included in the Iberian and/or the Mediterranean lists of tsunami events, as it is the case of the European GITEC Tsunami Catalogue, but there is a need to organize this information in a dataset and to assess the likelihood of claimed historical tsunamis in Morocco. Due to the fact that Moroccan sources are scarce, this compilation rely on historical documentation from neighbouring countries (Portugal and Spain) and so the compatibility between the new tsunami catalogue presented here and those that correspond to the same source areas is also discussed.

Improvements on the magnitude-geographic criterion of tsunami hazard

We suggest supplementing the MLH magnitude with the threshold (M thr) values of MPV, MSH, and MLH magnitudes (Russian scales), as well as M S and M W now in wide international use, for issuing tsunami alerts for hazards emanating from the main tsunamigenic zones of the Pacific Ocean. Relations are given to connect the MLH to these magnitudes. A comparative analysis applied to a catalog of large (M ≥ 6) earthquakes in the North Pacific and to the associated tsunami catalog gave the probabilities of false alerts and unpredicted tsunamis as functions of the threshold magnitude value (M thr). A two-step decision rule is proposed to issue tsunami alerts due to the tsunamigenic zones situated close to the Far East coast of Russia.

Tsunamigenik di Selat Sunda: Kajian terhadap katalog Tsunami Soloviev

http://dx.doi.org/10.17014/ijog.vol3no4.20086Tsunamigenic is a natural phenomena which is potential to generate a tsunami, such as water dis- turbance due to the presence of activities of volcanism, earthquakes, coastal and sub marine landslidse, or other causal factors . Historically, the Sunda Strait has experienced several tsunami events recorded in the tsunami catalog. Those tsunamies were caused by some geological phenomena such as eruptions of Krakatau submarine volcano in 416, 1883, and 1928; earthquakes in 1722, 1852, and 1958; and other causes which were suggested as a mass failure of coastal and submarine landslide in 1851, 1883, and 1889. Tectonic condition of the Sunda Strait is very complicated, because this region is located at the boundary of Indian-Australian and Eurasian Plates, where a unique island arc system occurs with its association such as trench, accretionary zone, volcanic arc and back-arc basin. Sunda trench as a plate boundary is the most potential region to produce big earthquakes. Existence of a seismic gap in the region can cause a stress accumulation and store energy, then it will be released any time as a big earthquake to generate a tsunami. Along eruption history, Krakatau volcanic arc has four stages of reconstruction and three stages of destruction, and every destruction stage produces tsunami which is suggested to be potentially repeated in the future in a period between 2500 to 2700. Seafloor of the Sunda Strait has an unstable geological condition due to geological structure development, which creates grabens and also enable to produce submarine landslides triggered by earthquake. Coastal condition around the Semangko and Lampung Bays consisting of steep topography with high intensity of weathering, is another factor to contribute landslide, particularly in the case of triggering be heavy rainfall between December to Februari. Furthermore, if landslide materials tumble into the water, even very small and locally, could create a potency of tsunami.

Tsunamigenik di Selat Sunda: Kajian terhadap katalog Tsunami Soloviev

http://dx.doi.org/10.17014/ijog.vol3no4.20086Tsunamigenic is a natural phenomena which is potential to generate a tsunami, such as water dis- turbance due to the presence of activities of volcanism, earthquakes, coastal and sub marine landslidse, or other causal factors . Historically, the Sunda Strait has experienced several tsunami events recorded in the tsunami catalog. Those tsunamies were caused by some geological phenomena such as eruptions of Krakatau submarine volcano in 416, 1883, and 1928; earthquakes in 1722, 1852, and 1958; and other causes which were suggested as a mass failure of coastal and submarine landslide in 1851, 1883, and 1889. Tectonic condition of the Sunda Strait is very complicated, because this region is located at the boundary of Indian-Australian and Eurasian Plates, where a unique island arc system occurs with its association such as trench, accretionary zone, volcanic arc and back-arc basin. Sunda trench as a plate boundary is the most potential region to produce big earthquakes. Existence of a seismic gap in the region can cause a stress accumulation and store energy, then it will be released any time as a big earthquake to generate a tsunami. Along eruption history, Krakatau volcanic arc has four stages of reconstruction and three stages of destruction, and every destruction stage produces tsunami which is suggested to be potentially repeated in the future in a period between 2500 to 2700. Seafloor of the Sunda Strait has an unstable geological condition due to geological structure development, which creates grabens and also enable to produce submarine landslides triggered by earthquake. Coastal condition around the Semangko and Lampung Bays consisting of steep topography with high intensity of weathering, is another factor to contribute landslide, particularly in the case of triggering be heavy rainfall between December to Februari. Furthermore, if landslide materials tumble into the water, even very small and locally, could create a potency of tsunami.

Emanuela Guidoboni/Alberto Comastri, Catalogue of earthquakes and tsunamis in the Mediterranean area from the 11th to the 15th century

Emanuela Guidoboni/Alberto Comastri, Catalogue of earthquakes and tsunamis in the Mediterranean area from the 11th to the 15th century

Tsunami hazards in the Eastern Mediterranean: strong earthquakes and tsunamis in the East Hellenic Arc and Trench system

Abstract. Data on tsunami phenomena occurring in the East Hellenic Arc and Trench system (HA-T) from antiquity up to the present have been updated, critically evaluated and compiled in the standard GITEC format developed in the last decade for the New European Tsunami Catalogue. New field observations are presented for the tsunamis of 9 February 1948 and 24 March 2002. From the 18 tsunamis reported eight are rather well-documented while another nine remain doubtful. The mean recurrence of strong tsunamis is likely equal to about 142 years. Most of the tsunamis documented are caused by strong earthquakes occurring in the area offshore Rhodes to the east or northeast of the island. However, there are large earthquakes near Rhodes that do not cause tsunamis, like the 1926 and 1957 ones, which is of particular importance for the tsunami hazard assessment.

Investigation on tsunami effects in the central Adriatic Sea during the last century – a contribution

Abstract. In this work we present the result of a study aimed at examining the Italian earthquake sequences that occurred in the area of the central Adriatic sea with the purpose of understanding whether some of them were accompanied by tsunami effects. The motivation for this research was the update and enrichment of the Italian Tsunami Catalogue. The result was that evidence was found for two new cases of earthquake-induced tsunamis: these are the August 1916 Rimini and the October 1930 Ancona events. The bulk of the present research consisted in collecting all the available data on the earthquakes that affected the selected area in the past century and in identifying those potentially capable of generating tsunamis. During the study all the available material was gathered, which includes specific monographs and scientific papers, articles available in contemporary chronicles and in local and national newspapers. The final result of this research will improve our knowledge of the tsunamigenic activity of the central Adriatic sea and contribute to the assessment of the tsunami hazard and risk along these coasts, that especially in the peak season form one of the most densely populated areas of the Italian peninsula with flat and large beaches and water front resorts crowded of tourists.

Tsunami hazard in the Eastern Mediterranean: strong earthquakes and tsunamis in Cyprus and the Levantine Sea

A modern tsunami catalogue has been compiled for the region of Cyprus-Levantine Sea in which 24 certain or possible local tsunamis are listed from antiquity up to the present time, while six regional tsunamis, generated in the Hellenic arc, are documented which affected the region. Another set of 13 doubtful events not included in the catalogue are discussed. Tsunami intensities k and K were re-evaluated using the classic 6-grade and the new 12-grade intensity scales, respectively. The strongest tsunamis reported in the region of interest are those of 551 AD, 749, 1068, 1201, 1222, 1546 and 1759, all occurring along the Levantine coast from Gaza northward, with the exception of the 1222 wave which occurred in the Cyprean arc. The causative earthquakes, however, occur on land and are associated with the left-lateral strike-slip Levantine rift and, as such, remain unexplained. In this paper we speculate on the mechanism of these events. A second tsunami zone follows the Cyprean arc, where the situation of subaqueous seismogenic sources favours the generation of tsunamis by co-seismic fault displacements. Submarine or coastal earth slumping, however, may be an additional tsunamigenic component. Based on historical data, the average tsunami recurrence in the Cyprus-Levantine Sea region is roughly estimated to be around 30 years, 120 years and 375 years for moderate (k/K ≥ 2/3), strong (k/K ≥ 3/5) and very strong (k/K ≥ 5/8) events, respectively. The rate of tsunami occurrence equals 0.033, 8.3 × 10−3 and 2.7 × 10−3 events/year for intensity k/K ≥ 2/3, 3/5 and 5/8, respectively. For a Poissonian (random) process the probabilities of observing at least one moderate, strong or very strong tsunami are 0.28, 0.01 and 3 × 10−3 within 1 year, 0.81, 0.34 and 0.13 within 50 years and 0.96, 0.56 and 0.24 within 100 years, respectively. The tsunami potential in the Cyprus-Levantine Sea area is low relative to other Mediterranean tsunamigenic regions. However, the destructiveness of some historical events indicates the need to evaluate tsunami hazard by all available means. In addition, remote tsunamigenic sources, such as those of 1303 and 1481 in the eastern Hellenic arc, are able to threaten the coasts of the Cyprus-Levantine region and, therefore, such regional tsunamis should be taken into account in the evaluation of the tsunami risk of the region.