Tsunami Catalogue Research Articles

Recent progress in tsunami deposit investigations in Taiwan

Abstract Identifying deposits of modern/historical and prehistorical tsunamis in Taiwan has been successful in the past two decades and has substantially increased the extant tsunami catalogs, which have been limited in the past four centuries due to scarce and ambiguous historical accounts. In this review, the initiation of the investigation is briefly discussed, partly in response to the latest catastrophic tsunamis in the Indo-Pacific and the stimulated public concern in Taiwan. Major developments and results of the investigation include the onset of the first stage before 2010, with findings in Keelung, the eastern coast, and Lanyu Island, and the second/ongoing stage after 2013, with findings in the northern and eastern coasts and Penghu Islands. These findings contributed to validating the debated historical events, expanding the event number and time span of the tsunami catalog, and elaborating on tsunami processes, which collectively enabled the delineation of the recurrence time intervals between events. Limitations, uncertainty, further contributions, and feedback are discussed including insights into the regional western Pacific hazards of tsunamis, earthquakes, and volcanic eruptions; the principles of recognizing tsunami deposits and processes; and the propositions of future studies and hazard mitigations in Taiwan.

Development of magnitude correlation equations for the tsunamigenic zones of the Indian Ocean

There is a pressing need for a homogonous tsunami catalogue for the Indian Ocean as nearly 20% of tsunami events worldwide affect the region. Any study on tsunami hazard assessment necessitates a homogenous tsunamigenic earthquake catalogue. The existing records of strong tsunamigenic earthquakes have the magnitudes expressed in moment magnitude (MW), body wave magnitude (mb), local magnitude (ML), and surface wave magnitude (MS). This study deals with developing regional magnitude correlation equations for tsunamigenic earthquakes of the Indian Ocean. The present investigation estimates the threshold magnitude and focal depth for an earthquake to turn tsunamigenic. It is found that earthquakes above MW ≥ 5.9 and focal depth ≤ 80 km have the potential to generate a tsunami in the region. The moment magnitude is the most proper scale to characterize the size of large tsunamigenic earthquakes as it is more directly related to the released energy and does not suffer saturation. Hence, equations have been developed to convert surface wave magnitude (MS) to moment magnitude (MW) using three types of regression models viz. standard regression (SR), inverse standard regression (ISR), and orthogonal standard regression (OSR). The efficacy of these models has been compared in terms of R-squared and residual analysis. This study indicates that OSR is the best-suited regression model for developing magnitude correlation equations for the three zones of the Indian Ocean region under study. Also, a single unified conversion equation for the whole of the Indian Ocean has been derived with rational accuracy.

Probabilistic Tsunami Risk Assessment from Incomplete and Uncertain Historical Impact Records: Mediterranean and Connected Seas

Tsunami risk is considered as the probability of a particular coastline being struck by a tsunami that may cause a certain level of impact (destructiveness). The impact metric of a tsunami is expressed in terms of tsunami intensity values, K, assigned on a 12-degree scale. To calculate tsunami risk we are based on the tsunami history of the region codified in tsunami catalogues. The probabilistic model adopted was used successfully for hazard assessment of earthquakes (Kijko et al. in Bull Seismol Soc Am 79:645–654, 2016) and of tsunamis (Smit et al. in Environmetrics 30:e2566, 2019) by considering seismic magnitude and tsunami height as metrics of the respective hazards. In this model, instead of hazard metrics we inserted risk metric, i.e. wave impact in terms of intensity values. The procedure allows utilization of the entire data set consisting not only from the complete (recent) part of tsunami catalogue but also from the highly incomplete and uncertain historical part of the catalogue. Risk is assessed in terms of probabilities of exceedance and return periods of certain intensity values in specific time frames. We applied the model using catalogues for the Mediterranean and connected seas. Sensitivity analysis showed that using complete data sets generally provided more realistic results than using entire data sets. Results indicated that the risk level depends on the seismicity level and not on the size of individual ocean basin. The highest tsunami risk level was found in the eastern Mediterranean (EM), with a significantly lower risk in the western Mediterranean (WM). In the Marmara Sea (MS), the tsunami risk was low, and the lowest was in the Black Sea (BS). The risk in the small Corinth Gulf (CG, Central Greece) was comparable to that of WM. The return period of damaging tsunamis (i.e. K ≥ 7) was 22 years in the entire Mediterranean basin and 31, 118, 135, 424, and 1660 years in the EM, WM, CG, MS, and BS basins, respectively.

Holocene offshore tsunami archive – Tsunami deposits on the Algarve shelf (Portugal)

The well-known 1755 CE Lisbon tsunami caused widespread destruction along the Iberian and northern Moroccan coastlines. Being affected by the powerful 1755 CE Lisbon tsunami, the southwestern Algarve shelf provides environments for detecting offshore tsunami imprints. Our multidisciplinary investigations (hydroacoustics, sedimentology, geochemistry, radiocarbon dating) of the Holocene sediments have revealed tsunami deposits linked to this tsunami and a ca. 3600 cal yr BP event. The latter event is until now unidentified in Portugal. Both event deposits contrast with the background shelf sedimentation by their coarser grain size, element composition, internal structure, and erosive base, making them discernible in the sub-bottom data and cores. Especially the ca. 3600 cal yr BP deposit is exceptionally well-preserved at one of the coring sites. The clear differentiation into several sections enables further insights into offshore tsunami transport and depositional processes. This study demonstrates that the record and preservation of tsunami deposits were possible on the Algarve shelf in specific locations sheltered from possible alterations. Our findings extend the tsunami catalogs of Portugal with a previously unknown tsunami dated to ca. 3600 cal yr BP.

Earthquake-Induced Tsunamis in Western Greece (Ionian Sea and Western and Southern Peloponnese): Use of Tsunami Quantities, Impact and ITIS-2012 Intensities for Highlighting Susceptible Areas

Taking into account recent studies on the tsunamigenic potential of strike-slip faults, it is concluded that there is a need to reassess their near-source tsunami hazard and risk. One of the areas which needs reassessment is Western Greece, especially the Ionian Islands and the western coastal Peloponnese, where major seismogenic strike-slip structures occur. In this context, an extensive review of the available literature is conducted, including not only earthquake and tsunami catalogues but also tsunamis’ imprints on the stratigraphic record. It is concluded that the Ionian Islands and the western Peloponnese have a rich history of tsunamis since 6000 BC, revealing that they are subjected to high tsunami hazard. In addition to the teletsunami effects of distant earthquakes, there are also local tsunamis with smaller physical quantities and slighter coastal impact that are attributed mainly to local offshore faults and earthquake-triggered landslides. The fact that no destructive local tsunamis have been detected so far does not exclude the possibility of future triggering. In order to identify areas susceptible to future tsunami impact, we extract tsunami quantities and coastal impact data from available sources and we apply the Integrated Tsunami Intensity Scale 2012 (ITIS-2012) for all the events with available and adequate information. The highly susceptible areas comprise straits, funnel-shaped bays and extensive coastal areas exposed to major strike-slip seismogenic sources in the Ionian Sea and the western Hellenic Trench. Based on the aforementioned information, the inclusion of the Ionian Sea in the tsunamigenic zones of Greece is strongly recommended.

Exploring of the spatially varying completeness of a tsunami catalogue

Exploring of the spatially varying completeness of a tsunami catalogue

The 373 B.C. Helike (Gulf of Corinth, Greece) Earthquake and Tsunami, Revisited

AbstractAncient authors report the destruction and drowning in 373 B.C. in the Gulf of Corinth (Greece) of Helike (Helice and Eliki), an important, nearly coastal town, and of Boura (Bura, Buris, Bouris, and Voura), another town in the hinterland, as a punishment by the ancient God Poseidon because of a serious crime committed in his shrine. This narrative has been regarded as a description of a true event, though with some exaggerations, and the 373 B.C. event is included in earthquake and tsunami catalogs. In the first part of this article, it is shown that (1) local natural hazards exclude the possibility (risk) of total loss of the ancient “polis” (town state) of ancient Helike because of its vulnerability due to its geography. (2) Systematic geoarchaeological studies confirm this prediction because they reveal essentially undisturbed archaeological layers predating and postdating 373 B.C., with no signs of a tsunami. (3) Archaeological excavations have recently brought to light, among other findings, remains of the harbor of Boura and of the shrine of Poseidon at Helike, as well as coins issued by Helike several decades after its alleged loss. This evidence permits a reconsideration of ancient texts related to the loss of Helike in a supervised learning-type approach. It was found that genuine ancient Greek texts do not mention any catastrophe of Helike, but rather that the legend of its total loss appeared several centuries later in Roman times, in local legends, rumors, and forged or manipulated ancient texts (e.g., by pseudo-Aristotle). The ancient legend became important because it explained the collapse of the town state of Helike and it fit ancient religious ideas in a tectonically active region because of the rapid burial (“disappearance”) of ancient Greek remains under sediments in a young delta and because of the prominent location of Helike in the seafaring route between Rome and the eastern Mediterranean.For earthquakes before our era, historical and archaeological data have attracted interpretations… attributing to earthquakes… the demise of flourishing city-states.…The reason for the revival of catastrophe hypotheses is perhaps that they are easy to explain. They are too simple, too obvious and too coincidental and chiefly because they have become fashionable in recent years. (Ambraseys, 2006)

The Oldest Report of a 1537 Mexico Tsunami Based on Japanese Literature Is Erroneous

Abstract According to the Global Historical Database by the National Centers for Environmental Information, the oldest historical tsunami record in Central America is the earthquake tsunami that occurred in Mexico in 1537; however, this record is doubtful because this tsunami is reported by no authority outside Japan. Here, I examined earthquake and tsunami catalogs and found the source of this suspicious data. Imamura (1925) compiled the first part of the chronological table of major earthquakes in the world from the earthquake catalog of the world by Milne (1912). During this compilation, information on the tsunami caused by the 1531 Spain–Portugal earthquake was not copied. The chronological table was published almost annually until 1962; during this time the table was revised in 1958 by Kawasumi, who was the author in charge at the time. The remarks for the 1531 Spain–Portugal earthquake tsunami should have been added during the revision, but the text “tsunami existence” was erroneously added to the next entry for the 1537 Mexico earthquake. The source of the 1537 tsunami report was this miscopy.

Italian Tsunami Effects Database (ITED): The First Database of Tsunami Effects Observed Along the Italian Coasts

Traditional tsunami catalogues are conceived as a collection of tsunamis classified by the generating cause, providing a general description of the effects observed for each tsunami. Those catalogues, even if they provide fundamental information, are not suitable for producing an exhaustive picture of the geographical distribution of the tsunami effects. In this paper we introduce the new Italian Tsunami Effects Database (ITED), a collection of evidence documenting the effects along the Italian coasts from historical times to present. The database comes forth the Euro-Mediterranean Tsunami Catalogue (EMTC) and focusses on the effects of tsunamis observed along the Italian coasts providing descriptive and quantitative information for each OP. The information reported in ITED does not only concern the effects produced by Italian tsunamis, but also those effects produced by tsunamis originated outside the Italian territory. ITED contains 318 OPs, related to 73 Italian tsunamis and to four tsunamis which occurred outside Italy. The database can be accessed through a WebApp that displays for each OP the description of effects, quantitative data (run-up, inundation, withdrawal, etc.) and tsunami intensity with the corresponding bibliographic references. The database also provides the tsunami intensity distribution along time (tsunami-history) for each site, allowing the end user to know how a place has been affected by tsunamis over the time. The information contained in ITED makes this database a useful tool to understand how tsunamis have affected the Italian territory and emphasizes the importance of studying the tsunami hazard along the Italian coasts.

Sand Ridges on Rocky Coastal Platforms as Markers of Tsunami Impact: A Multi-Disciplinary Analysis along the Ionian Coast of Southern Apulia (Italy)

Along the Ionian coast of Southern Apulia, a sand ridge has been detected at the inner border of a wide, low-elevated rocky platform. A multi-disciplinary analysis was carried out to define the main geomorphological and sedimentological features of this dune-like coastal deposit, to clarify its nature as well as to obtain chronological constraints for its development. The geomorphological survey reveals that the sand ridge is about 40–60 m wide, reaching a maximum elevation of 3.9 m above m.s.l., whereas its thickness can be estimated between 1.0 and 2.8 m. The sand ridge is in some places associated with large-size boulders. Grain size analysis shows that it is made up of poorly sorted coarse-medium sands with a gravelly fraction, without significant sedimentary structures, as confirmed by Ground Penetrating Radar survey. The micro and macro-faunal assemblage sampled in the sand ridge can be related to shallow-water environments with Posidonia oceanica meadows occurring offshore. The development of the studied sand ridge can be ascribed to a tsunami event able to mix up very coarse bioclastic sands placed at submerged platforms, storm beach deposits covering the low-elevated coastal platform in patches, and possibly older tsunami deposits. Accelerator Mass Spectometry radiocarbon age determinations on mollusc shells sampled from the sand ridge span from 929–1168 AD to 1707–1950 AD and cluster around the 18th–19th centuries, suggesting a possible association with a recent tsunami event. Data reported in the Euro-Mediterranean Tsunami Catalogue would indicate as the most likely event that one of the 25th April 1836, produced by a strong earthquake with its epicenter near Rossano village, on the Ionian coast of the Calabria region.

Revision of the Azorean catalogue of tsunamis

Abstract The Azores islands, owing to their complex geographical and geodynamic setting, are exposed to tsunami events associated with different triggering mechanisms, local or distant. Since the settlement of the Azores, in the fifteenth century, there have been numerous accounts that relate coastal area flooding episodes with unusually high waves that caused death and destruction. In this work is presented a review and a characterization of the different events registered in the archipelago that can be associated with tsunamigenic phenomena. For this purpose, diverse documentation was collected such as chronics, manuscripts, newspaper articles and magazines, scientific publications and international databases available online. Thus, new relevant information allowed better characterization of some events. Furthermore, it was possible to add new entries and to discard others included in previous compilations owing to a lack of quality in historical sources or instrumental records. Some teletsunamis, among them the 1 November 1755 which killed six people on Terceira Island, regional and local tsunamis were identified. Although the majority of these events result from tectonic sources, some were also triggered by landslides, such as the 9 July 1847 Quebrada Nova tsunami which killed 10 people on Flores and Corvo islands, and by meteorological phenomena.

Update of the tsunami catalogue of New Caledonia using a decision table based on seismic data and marigraphic records

Abstract. Fourteen years ago, the 26 December 2004 Indian Ocean tsunami demonstrated the destructional capability of tsunamis to the entire world. Since then, many research programs have been initiated to try to understand the phenomenon and its related hazards better and to improve the early warning systems for exposed coastal populations. Pacific Islands Countries and Territories (PICTs) are especially vulnerable to tsunamis. Amongst them, New Caledonia is a French overseas territory located in the Southwest Pacific and exposed to several tsunami sources. In 2010, a catalogue of tsunamis that were visually observed or measured in New Caledonia was published. Since this first study, several events occurred between 2009 and 2019, and an update of this catalogue was necessary within the framework of a tsunami hazard assessment project in New Caledonia (TSUCAL). To complete this catalogue, a decision table has been designed to select potential tsunamigenic events within the USGS earthquake database, using criteria on the distance to New Caledonia, the magnitude and the hypocenter depth. Then a cross-comparison between these earthquakes, the NOAA National Geophysical Data Center (NGDC) tsunami catalogue and local tide gauge records provided 25 events that were recorded in New Caledonia for the period from 30 September 2009 to 10 January 2019. These events are added to the 12 events reported with certainty during previous studies, leading to a number of 37 tsunamis triggered by earthquakes reported or recorded in New Caledonia since 1875. Six of them have been identified only thanks to local tide gauges, supporting the fact that instrumental recording of tsunamis is paramount for tsunami hazard studies, from early warning to the validation of coastal models. In addition, unpublished tide gauge data are provided for the 1960 Chile tsunami.

Tracing tsunami signatures of the ad 551 and ad 1303 tsunamis at the Gulf of Kyparissia (Peloponnese, Greece) using direct push in situ sensing techniques combined with geophysical studies

AbstractThe western Peloponnese was repeatedly hit by major tsunami impacts during historical times as reported by historical accounts and recorded in earthquake and tsunami catalogues. Geological signatures of past tsunami impacts have also been found in many coastal geological archives. During the past years, abundant geomorphological and sedimentary evidence of repeated Holocene tsunami landfall was found between Cape Katakolo and the city of Kyparissia. Moreover, neotectonic studies revealed strong crust uplift along regional faults with amounts of uplift between 13 m and 30 m since the mid‐Holocene. This study focuses on the potential of direct push in situ sensing techniques to detect tsunami sediments along the Gulf of Kyparissia. Direct push measurements were conducted on the landward shores of the Kaiafa Lagoon and the former Mouria Lagoon from which sedimentary and microfaunal evidence for tsunami landfall are already known. Direct push methods helped to decipher in situ high‐resolution stratigraphic records of allochthonous sand sheets that are used to document different kinds of sedimentological and geomorphological characteristics of high‐energy inundation, such as abrupt increases in grain size, integration of muddy rip‐up clasts and fining upward sequences which are representative of different tsunami inundation pulses. These investigations were completed by sediment coring as a base for local calibration of geophysical direct push parameters. Surface‐based electrical resistivity tomography and seismic data with highly resolved vertical direct push datasets and sediment core data were all coupled in order to improve the quality of the geophysical models. Details of this methodological approach, new in palaeotsunami research, are presented and discussed, especially with respect to the question of how the obtained results may help to facilitate tracing tsunami signatures in the sedimentary record and deciphering geomorphological characteristics of past tsunami inundation. Using direct push techniques and based on sedimentary data, sedimentary signatures of two young tsunami impacts that hit the Kaiafa Lagoon were detected. Radiocarbon age control allowed the identification of these tsunami layers as candidates for the ad 551 and ad 1303 earthquake and tsunami events. For these events, there is reliable historical data on major damage on infrastructure in western Greece and on the Peloponnese. At the former Mouria Lagoon, corroborating tsunami traces were found; however, in this case it is difficult to decide whether these signatures were caused by the ad 551 or the ad 1303 event.

Assessment of the tsunami hazard on the Russian coast based on a new catalogue of tsunamis in the Black Sea and the Sea of Azov

We present the results of work on the compilation of a fuller and more comprehensive historical catalogue of earthquakes and tsunamis in the basin of the Black Sea and the Sea of Azov, an area of primary importance for the Russian Federation. In the 20th century, there were no significant tsunamis in the Black Sea; therefore, its coast was not considered tsunami-prone. A systematic search for new data sources, a revision of earlier ones, and the use of new approaches to the identification of tsunamigenic events resulted in a more than doubling of the number of known tsunamigenic events in this basin, bringing it up to 50. The total length of the new tsunami catalogue reached 3000 years, which makes it the second longest after the Mediterranean tsunami catalogue (about 4000 years). Taking into account the seismotectonic features of the Black Sea region, we processed data on historical tsunamis and analyzed the geographical and temporal distributions of their sources. For all tsunamigenic events we performed a parameterization of available information about their sources and coastal manifestations, evaluated the tsunami intensity based on the Soloviev-Imamura scale, and proposed a classification of tsunami and tsunami-like water wave disturbances based on their genesis. Tsunami run-up heights, inland penetration, and damage were estimated with regard for the newly found data. Among the identified historical events, there are devastating tsunamis with run-ups of 4-5 m, sometimes up to 6-8 m, which resulted in disastrous consequences for several ancient cities (Dioscuria, Sebastopolis, Bizone, and Panticapaeum) and many coastal settlements. Expert assessments of the most tsunami-prone areas of the coasts are given.

Possible tsunami inundation identified amongst 4–5th century BCE archaeological deposits at Tel Ashkelon, Israel

The eroding coastal sections of Ashkelon, Israel contain exposed sequences of natural and anthropogenic sedimentological deposits; some of unknown origin. Ashkelon, an important and long-occupied ancient coastal city, is directly referred to within written records of past tsunami events yet field studies and archaeological descriptions have not yet corroborated these claims. This is not unusual, nor unexpected, given the amount of anthropogenic and natural disturbance that can erase the sedimentary remains, as well as the relatively recent advancements in identifying such deposits. A sequence of sediments at the base of an eroding coastal archaeological section shows clear waterborne transport characteristics and was previously interpreted as alluvial; however, no alluvial sources could be associated to the deposit. In this study, the sedimentological characteristics of this section were described and analyzed in greater detail to determine their nearest similarity to possible transport mechanism such as storms, rivers, and tsunamis. The deposits contain fining-upward sequences, rip-up clasts, imbricated inclusions, fine mud layers, microfauna (foraminifera), and broken diagnostic pottery from the 4–5th c. BC Reconstructions of the coastline at the time of the event place the sampled profile at least 100m inland from the shoreline, at an elevation +2.0 to 2.4m above sea level. River-channel features were not identified in the section. For this area, modern observations of major storms show inundations of <75m which are not coupled with depositional deposits (erosional only), suggesting that these deposits are not storm-related. Rather, it is possible that the deposits support the arrival of an undocumented tsunami at Ashkelon some time following the 4–5thcenturyBCE. These results reinforce the importance of the reassessment of many coastal sedimentological studies in light of improved capabilities of recognizing possible tsunamigenic sediments, as well as increased field efforts for the purpose of producing more complete tsunami catalogues; and also highlights the need to better record and document eroding coastlines that may contain valuable information regarding both anthropogenic and natural history.

A new chalcolithic-era tsunami event identified in the offshore sedimentary record of Jisr al-Zarka (Israel)

Tsunami field evidence is a critical resource for determining coastal risk. However, in many cases there is low potential for long term preservation of such deposits on land. A growing body of evidence suggests that tsunami deposits can be present in the shallow offshore realm and may present a largely untapped, but important worldwide sedimentological reference set for investigating past tsunami events. Here, different proxies for tsunami sediment identification and differentiation (granulometry, XRD, XRF, FT-IR) were used to determine the presence or absence of such deposits in a core collected offshore at Jisr al-Zarka, midway between Tel Aviv and Haifa. The study aimed to recognize anomalous deposits and test different analytical methods to define their origins. Five anomalous sedimentological horizons were identified, four of which were interpreted as tsunamigenic by comparison to previously identified poorly sorted, shell-rich tsunamites found nearby in Caesarea and contrast to the fine-sand, Nile-derived background sediments. The remaining anomaly was distinctive, but not determined to be tsunamigenic due to a lack of coarse shell in the matrix. The oldest tsunamigenic layer, coinciding with the Chalcholithic cultural period (5.7ka), is the oldest such deposit identified offshore Israel to date and the non-tsunamigenic anomalous horizon may correspond with a transitional climatic phase (~5.5ka). This research reinforces the importance of offshore investigations as a means of improving tsunami catalogues and identifying environment-altering events.

Tsunamis recorded in tide gauges at Costa Rica Pacific coast and their numerical modeling

Here we perform an inventory of tsunamis recorded by tide gauges in the Pacific coast of Costa Rica. This paper also reveals nine tsunami records that had not been published before, at Puntarenas tide gauge corresponding to the 1979 Colombia tsunami and at Quepos tide gauge corresponding to the 1985 Mexico twin tsunamis, the 2010, 2014 and 2015 Chile tsunamis, the 2006 Tonga tsunami, the 2011 Japan tsunami and the 2013 Solomon Islands tsunami. The original record of 1990 Cobano tsunami at Quepos was digitized again at a higher resolution and re-processed. The arrival of 1979, 1985, 2006 and 2014 tsunamis to Costa Rica is not listed on tsunami catalogs. The maximum tsunami height obtained here after processing 1990, 2011 and 2013 records was higher than reported on catalogs. The opposite happened for the 2010 tsunami. Quepos gauge record for January 2007 was analyzed as it seemed to have registered the Kuril Islands tsunami, but the results were not conclusive due to the low sample rate and the small tsunami amplitude if any. All those eleven tsunamis were modeled and the results compared with the records. A good agreement was obtained for the Quepos gauge, although the modeled 2011 and 2013 tsunamis had a difference of 8 min on the arrival time. An acceptable agreement was obtained for the Puntarenas gauge for 1979 tsunami, considering at least the first 4 h of the marigram is lost.

Probabilistic Tsunami Hazard Assessment from Incomplete and Uncertain Historical Catalogues with Application to Tsunamigenic Regions in the Pacific Ocean

The paper presents a new method for empirical assessment of tsunami recurrence parameters, namely the mean tsunami activity rate $$\lambda_{\text{T}}$$ , the Soloviev–Imamura frequency–magnitude power law $$b_{\text{T}}$$ -value, and the coastline-characteristic, maximum possible tsunami intensity $$i_{ \text{max} }$$ . The three coastline-characteristic recurrence parameters are estimated locally by maximum likelihood techniques using only tsunami event catalogues. The method provides for incompleteness of the tsunami catalogue, uncertainty in the tsunami intensity determination, and uncertainty associated with the parameters in the applied tsunami occurrence models. Aleatory and epistemic uncertainty is introduced in the tsunami models by means of the use of mixture distributions. Both the mean tsunami activity rate $$\lambda_{\text{T}}$$ of the Poisson occurrence model, and the $$b_{\text{T}}$$ -value of the Soloviev–Imamura frequency–intensity power law are random variables. The proposed procedure was applied to estimate the probabilities of exceedance and return periods for tsunamis in the tsunamigenic regions of Japan, Kuril–Kamchatka, and South America.

Assessment of Tsunami-related Geohazard Assessment for Coasts of Hersek Peninsula and Gulf of İzmit

Tsunamis are one of the most dreadful natural disasters; they could cause abysmal damage to all kind of lives in the hinterland within instantly. It is a major right-lateral moving fault that runs along the tectonic boundary between the Eurasian Plate to the north and the Anatolian Plate to the south. The western segment of the North Anatolian Fault splits into three main branches. The northern one of NAF is generally subdivided in several subsegments that have been the source of frequent large historical earthquakes. The Sea of Marmara coasts is located on the western extension of the NAFZ which is one of the most important active faults with strike-slip characteristics, which are not likely to generate tsunami. However, in the light of tsunami catalogs based on historical documents, it is possible to say that Sea of Marmara has tsunamigenic potential. The İstanbul shorelines, Gemlik Bay, Kapıdağ N-NE shores, Gelibolu, Hersek Peinsula and Gulf of İzmit are one of the most significant geohazards in Sea of Marmara due to the tsunami effect.

Updated Tsunami Catalog for the Jalisco‐Colima Coast, Mexico, Using Data from Historical Archives

ABSTRACT Modern earthquakes and tsunamis catalogs available online are compilations of earlier catalogs that included some inaccurate information. Here, we present a thorough revision of tsunamigenic earthquakes that, in historical time, have affected the Mexican Pacific coast between Jalisco and Colima. This area is located in a complex tectonic setting where the Rivera–Cocos and North American plates have produced four M ≥8 earthquakes and two big tsunamis since the nineteenth century. We identified tsunamigenic earthquakes that were not previously documented in modern earthquake and tsunami catalogs available online through a careful reading of original historical archives and documents. Our results indicate the occurrence of 21 events; among those we report 2 earthquakes documented for the first time (1563 and 1816) for the Jalisco‐Colima coast, and 8 large or medium intensity tsunamis also first reported (1816, 1818, 1900 [two tsunamis], 1911, 1933 [two tsunamis], and 1941) through documentary evidence. Our results demonstrate the need for a thorough investigation of historical documents and geological evidence of earthquakes and their tsunamis to accurately assess seismic and tsunami hazard.