In response to the tragic tsunami on 26 December 2004, in which over 250,000 lives were lost around the Indian Ocean region, the Intergovernmental Oceanographic Commission of UNESCO (UNESCO/IOC) received a mandate from the international community to coordinate the establishment of an Intergovernmental Coordination Group (ICG) for each region: the Caribbean, the Atlantic and Mediterranean basins and the Indian Ocean, to guide the development of tsunami warning centres in those areas.
An end-to-end tsunami warning system begins with the rapid detection of a tsunami wave and ends with a well prepared community that is capable of responding appropriately to a warning. An effective end-to-end tsunami early warning system could save thousands of lives in a tsunami event.
The operation of a tsunami warning centre is a vital part of an end-to-end tsunami warning system. A tsunami warning centre is not only involved in acquiring and processing data for detecting a tsunami, but also in formulating and disseminating tsunami warnings and connecting with communities at risk to ensure that they understand the warning and have the capacity to respond.
End to End TEWS
Source: U.S. Indian Ocean Tsunami Warning System Program (US IOTWS). 2007. Tsunami Warning Center. Reference Guide supported by the United States Agency for International Development and partners, Bangkok, Thailand. 311 p.
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World Tsunami Awareness Day, 2020
Italy joining the tsunami ready global community
Kos, Greece and Bodrum, Turkey Tsunami ready
Israel is getting ready against tsunamis
UNESCO Disaster and Risk Reduction
Manuals and guides; 69
Manuals and guides. Languages: English.
Manuals and guides; 65
Manuals and guides; 61
The IOC UNESCO organized an online project kick-off workshop on ‘Strengthening the Resilience of Coastal Communities in the North-East Atlantic, Mediterranean Region to the Impact of Tsunamis and Other Sea Level-Related Coastal Hazard on 17th and 20th December 2021. The 2.5-year project is financially supported by the European Union Directorate-General for European Civil Protection and Humanitarian Aid Operations (DG ECHO). The project aims to improve understanding of tsunami and sea-level related risks, develop better communication strategies, enhance real-time detection and monitoring capacities, improve alert and warning capacity. The project aims to implement at least seven Tsunami Ready recognized communities by 2023 in the seven selected countries: Cyprus, Egypt, Greece, Malta, Morocco, Spain and Turkey. Dr Denis Chang Seng, Programme Specialist, and Technical Secretary of IOC ICG/NEAMTWS highlighted that the key objectives of the workshop were to officially launch the new project, introduce country project partners and technical support countries, and establish a better understanding of the national and local context. The project is now named ‘CoastWAVE Project’. Mr Bernardo Aliaga, Head of Tsunami Unit (a.i) expressed his gratitude for the renewal of fruitful cooperation between IOC UNESCO and the EU ECHO in the Mediterranean region concerning tsunami early warning and mitigation system. Dr Vladimir Ryabinin, the Executive Secretary of IOC in his opening remarks thanked EU DG ECHO and the Joint Research Centre (JRC) for strong cooperation and collaboration with IOC UNESCO. He said the project is timely and fits the development of the Tsunami Programme. The Decade of Ocean Science for Sustainable Development provides an opportunity to co-design and work with the tsunami community in the Mediterranean region. Mr Peter Billing, EU DG ECHO underlined the excellent long-standing cooperation with UNESCO. The new project aligns with the new ECHO approach on Disaster Risk Reduction on reinforcing local preparedness and education to reduce coastal hazard impacts. He stressed that it is an opportune time to take advantage of lessons learned and share experiences, as well as take benefit of the new IOC UNESCO Tsunami Ready Community programme, a tool to reinforce local preparedness and resilience. Dr Nikos Kalligeris, the Tsunami National Contact and project focal point of Greece, delivered an opening remark prepared by the ICG/NEAMTWS Chair Prof Maria Ana Baptista. The new project initiative is paramount to NEAMTWS, especially considering the rare, but high impact of tsunami events due to high population exposure and tourism activities in the Mediterranean region.
Dr Denis Chang Seng then elaborated on the project details covering several issues including the tsunami hazard and risk context, past and recent events, increasing coastal exposure, as well as the justification for the project intervention. He stressed that CoastWAVE project aims to build upon ongoing achievements, in particular the Joint Research Centre (JRC) the European Commission Last Mile project. Two project staff are expected to be on board by January 2022.
Project partner countries provided presentations concerning the national and local context, including information concerning national project focal point, nominated Tsunami Ready community site, potential project partners and stakeholders, as well as preliminary information concerning the status of risk knowledge, communication strategies, early warning and mitigation system in the proposed/nominated community site. Dr Mathieu Péroche (France) and Dr Alessandro Amato (Italy) shared their experience concerning the ongoing efforts towards implementing the Tsunami Ready community in Cannes and three municipalities in Italy.
The CoastWAVE kick-off workshop was attended by over 35 participants.
The Intergovernmental Coordination Group for the Tsunami Early Warning and Mitigation System in the North-Eastern Atlantic, the Mediterranean and Connected Seas (ICG/NEAMTWS) held its 17th session of the ICG/NEAMTWS online between 24-26 November 2021. Despite the ongoing health pandemic, important progress has been achieved during the inter-sessional period. The Group welcomed the approval of a new IOC European Union DG-ECHO (European Civil Protection and Humanitarian Aid Operations) NEAMTWS project on “Strengthening the Resilience of Coastal Communities in the North-Eastern Atlantic, Mediterranean Region to the Impact of Tsunamis and Other Sea Level-Related Coastal Hazards. The project will help drive and shape the establishment and enhancement of tsunami early warning systems in several countries. An important milestone reported is the finalization of a new ICG/NEAMTWS 2021-2030 Strategy in line with the UN Ocean Science Decade for Sustainable Development. The Group encouraged Member States and partners to contribute to its implementation. Another key achievement is the successful results of the fourth tsunami exercise for the region, NEAMWave21 conducted between 8-10 March 2021 and the major increase in media interest.
First tsunami end-to-end exercise, 5 Nov 2021, Marsaxlokk, Malta Source: Denis Chang Seng
There is also continued national efforts in several countries to increase awareness on tsunami hazards and preparedness in line with and as contributions to the World Tsunami Awareness Day, 5 November 2021, and the tsunami exercises conducted in France and Malta. There is progress made by communities of Bouches-du-Rhône and Cannes (France); Kos (Greece); Israel; Minturno, Pachino, Palmi (Italy); Marsaxlokk (Malta); Azores, Cascais, Lagos, Lisboa, Madeira, Portimão, Setúbal (Portugal); Chipiona (Spain), Bodrum and Istanbul (Turkey) towards becoming Tsunami Ready and prepared. A new Task Team on Tsunami Ready was also established at the ICG/NEAMTWS-XVII session.
Another accomplishment is the study prepared by the Secretariat on Coastal Multi-Hazard Risk Perception, Resilience and Survey Questionnaires to contribute to the implementation of the new project concerning understanding and communication strategies of tsunami and other sea-level related risks. The session also appreciated the support of the European Commission (EC) and the Joint Research Centre (JRC), especially for the Last Mile Project Phase 2 implemented in Malta, and the support provided to the organisation of the first end-to-end tsunami exercise on 5 November 2021.
The Group set a target to establish at least ten Tsunami Ready recognized communities in Mediterranean countries in the next two years, contributing to making 100% of communities at risk of tsunami prepared for and resilient to tsunamis by 2030 through the implementation of the UNESCO/IOC Tsunami Ready Programme and other initiatives.
The session decided to organize and conduct the NEAMWave 23 tsunami exercise within the first week of the World Tsunami Awareness Day, 5 November 2023. The Seventeenth Session of the ICG/NEAMTWS was attended by around 78 participants from 16 member countries and a few observers.
The La Palma volcano eruption is generating headlines. The world has been captivated by the footage and images of the volcanic eruption and flowing lava in La Palma Island, in the Canary Archipelago. Part of the Cumbre Vieja (meaning “Old Summit”) volcano's main cone is reported to have collapsed amid an increase in "effusive activity". Lava reached the sea last week, forming a huge promontory (locally named “fajana”) on La Palma coast. It is estimated that over 1,000 buildings have been affected so far by the lava flow, with 6,000 people evacuated. The Spanish Prime Minister, Pedro Sánchez, visited La Palma and promised a 206 million Euro recovery package. On the other hand, many speculate and fear a possible associated, landslide-induced tsunami risk. There are concerns in the region about the possible flank collapse of Cumbre Vieja triggering a large tsunami. Questions include what is the likelihood and size of any landslip, tsunami detection and monitoring capability in the region and what could be the likely impacts?
Lava has been flowing down the Cumbre Vieja volcano's western flank towards the sea since Sept 19, 2021. PHOTO: EPA-EFE.
First, it is difficult to predict a landslip that triggers a tsunami. Mercedes Ferrer and others found in 2021, historical records of geological evidence and geochronological data of at least five megatsunamis in Tenerife, Lanzarote, and Gran Canaria, triggered by island flank mega landslides, and occasionally explosive eruptions, during the last 1 million years. Additionally, Inés Galindo and others presented a study in 2021, about a tsunami that was produced by the Argaga (La Gomera) landslide in 2020. However, Carracedo and others published in 1999 and 2001 that most volcanoes in the island required longer time periods to reach a critical level and when they reached it, there were more clear evidence of a possible flank collapse. For example, the landslip in La Palma, that created the Taburiente Caldera and the Aridane Valey, occurred 560 kyr ago and took hundreds of thousands of years to reach its critical level of instability, in contrast Cumbre Vieja was only formed about 125 kyr ago.
Recently, a research study conducted by French scientists about a possible La Palma landslide induced tsunami found that in the likelihood of a maximum slide volume (i.e., 80 km3) the wave impact is high on surrounding islands and coasts, as well as on the most exposed remote coasts such as Guadeloupe, located in the path of maximum wave energy. In Europe, the study found that the wave impact is high (for specific areas in Spain and Portugal) to moderate (Atlantic French coast), and moderate to weak along the French Atlantic coast. Smaller slide volumes (i.e., 40 and 20 km3) would have moderate impacts on these remote areas. The study provides certain insights concerning potential landslide and impacts. Helène Hebert, CENALT, France, said that this new study is suggesting revising the transoceanic models following an extreme worst-case scenario in La Palma. This study employs scenario analysis of different slide volumes.
Other scientists like Professor Mauricio Gonzalez, Universidad de Cantabria, Spain cautioned that the interesting issue would be to assess whether there is actually the possibility of a collapse of the island of La Palma that could generate a macro-tsunami. Professor Miquel Canals (University of Barcelona), an expert in marine geology mentions that, in contrast to other island flanks in the Archipelago, the western flank of La Palma is not buttressed, this means that extensive magma intrusions would tend to push such flank seawards, eventually generating a large tsunami. Seafloor and sub-seafloor evidence west of La Palma documents the occurrence of giant flank landslides in the past. However, such a worst-case scenario is very unlikely to occur under the current eruptive setting, which affects a limited section of Cumbre Vieja. In any case, monitoring the evolution of the on-going eruption is critical in terms of adoption of geo-hazard prevention measures.
While the discussion continues, focus is shifted towards the tsunami early warning system for the observation and detection of a possible tsunami. The Intergovernmental Coordination Group for the North-eastern Atlantic, the Mediterranean and Connected Seas Tsunami Early Warning and Mitigation System (ICG/NEAMTWS) of the IOC/UNESCO, is the current body concerned with Tsunami early warning in the region. It was formed in response to the tragic Indian Ocean tsunami event of 26 December 2004, which caused major damage and took over 250,000 lives. The ICG/NEAMTWS consists of five accredited Tsunami Service Providers (TSPs) in France (CENALT), Italy (INGV), Greece (NOA-HL-NTWC), Portugal (IPMA) and Turkey (KOERI). The Centre d’Alerte aux Tsunamis (CENALT, France) and the Portuguese Institute for Sea and Atmosphere (IMPA, Portugal) monitor seismic activity, coastal sea level, and provide free tsunami information and services to subscribed member states within the North-eastern Atlantic region.
Dr. Denis Chang Seng, IOC UNESCO Programme Specialist and ICG/NEAMTWS Technical Secretary, pointed out that the current Tsunami Early Warning and Mitigation System (TEWS) is not technically designed or optimised for volcano-landslip induced tsunamis. These situations remain a challenge and a limitation for TEWS across the globe. This was clearly demonstrated following the collapsed into the ocean of a large portion of the southern flank of the Anak Krakatau volcano on 23 December, 2018, causing a tsunami that swept the Lampung Province of Indonesia. The event killed dozens of residents and destroyed hundreds of houses. Following the eruption, the Joint Research Center (JRC) of the European Commission, collaborated with the local institutions in Indonesia to design and implement an emergency Tsunami Warning System for the Anak Krakatau volcano based on the installation of a number of Inexpensive Devices for Sea Level Measurement (IDSLs) around the Island’s volcano. Dr. Alessandro Annunziato, (JRC, European Commission) said that they are rapidly responding to a request from the Instituto Geográfico Nacional (IGN) of Spain for the provision of a new emergency IDSL, to be installed in the harbour of Tazacorte, on the western coast of La Palma Island, downhill of Cumbre Vieja’s on-going volcanic eruption. The objective is to monitor the sea level as close as possible to the volcanic source. The installation will take place after 20 October. The IDSL data logger software include routines that analyze the signals in real time and send them as messages/information about the detected wave anomalies to a list of prescribed users (SMS and email).
Stromboli, Italy, is also a good example to highlight volcanic induced tsunami events and experiences in the Mediterranean region. On 30 December, 2002, a part of the Sciara del Fuoco collapsed due to critical volcanic activity and associated lava flow, causing a landslide of 18 million cubic meters of material. Seismic wave recordings showed that the detachment of the wall occurred in two separate close phases, in fact, the landslide was first triggered in the submerged part of the Sciara and then spread to the surface part. The underwater landslide generated a sequence of tsunami waves that in a very short time intersected the whole island of Stromboli, the Northern part of the island of Panarea and eventually reached the other islands of the Eolian Archipelago, along the Messina and Calabria coasts. The maximum height reached by the tsunami wave on the coast, reported during the monitoring phase, was above 10m in many parts of the island of Stromboli. Presently, public authorities in Stromboli have developed designated mapped hazard zones, public displays of tsunami information, community-based tsunami evacuation maps, as well as outreach and public education materials. Tsunami hazards are fully addressed in the Community’s Emergency Operation Plan (EOP).
Stromboli, Italy tsunami mitigation and preparedness. Dipartimento della Protezione Civile, Italy.
The UN Ocean Decade Societal challenge on a Safe Ocean and the Tsunami Decade Programme are also focused on addressing the challenges concerning tsunamis from multiple sources (e.g. seismic events, volcanic explosions, coastal and underwater landslides). The ongoing, “Tsunami Ready Pilot Programme”, is an important tool to prepare vulnerable coastal residents to tsunamis, in particular those triggered close to the coast with a very short time to evacuate. In the NEAM region, member states have formally began work towards a Tsunami Ready recognized coastal communities such as Cannes (France), Marzamemi, Minturno, and Palmi (Italy), and Chipiona (Spain). In addition, a new project funded by the European Union Civil Protection and Humanitarian Aid Operations (ECHO), will also support the implementation of Tsunami Ready communities in several countries, including Morocco and Spain (Chipiona).
Education, drills and exercises are key to increase awareness and response of vulnerable communities to tsunami events. The last NEAM tsunami exercise (NEAMWave21) was held on 8-10 March 2021 with the participation of subscribed member states in a joint tsunami scenario conducted by CENALT (France) and IPMA (Portugal) based on the 1755 and magnitude 8.6 Lisbon earthquake and tsunami that had a major impact in Portugal, Morocco and Spain. The IOC/UNESCO and Member States, in collaboration with key partners are fully engaged in reducing sea level related coastal hazard risks, including tsunami through effective and enhanced Tsunami Early Warning and Mitigation System in the NEAM region.
An international team coordinated by INGV presents a new model for tsunami early warning following an earthquake
Realized a forecasting model that includes a quantitative estimate of uncertainties, linking it to the definition of tsunami alert levels
The Probabilistic Tsunami Forecasting (PTF) is the innovative procedure that allows, in real time, the determination of the tsunami alert level taking into account the inevitable uncertainty on the forecast of the tsunami. The procedure, which could introduce a paradigm shift in the management of tsunami alerts, was developed by an international research team coordinated by the Istituto Nazionale di Geofisica e Vulcanologia (INGV - National Institute of Geophysics and Volcanology) and it has just been published in the study “Probabilistic tsunami forecasting for early warning” in the scientific journal ‘Nature Communications’.
“The PTF quantifies the probability of occurrence of a tsunami with a given intensity within a few minutes after the shock capable of generating it", explains Jacopo Selva of the INGV Tsunami Warning Center (Centro Allerta Tsunami, CAT-INGV) and first author of the article. The method developed by the researchers rigorously and for the first time evaluates the unavoidable degree of uncertainty in real-time tsunami forecasts. “This offers the possibility to link the definition of the alert levels for tsunami early warning to the forecast of the intensity of the possible tsunami and to the relative uncertainty, based on pre-established risk reduction criteria”, adds Jacopo Selva.
“The forecasts are made by combining the earthquake parameters estimated in real-time with those expected in the area and, finally, with millions of numerical simulations of the tsunami propagation pre-calculated thanks to modern supercomputers”, adds Stefano Lorito, co-author of the study.
The research team applied the PTF, a posteriori, to several seismic events, including the 8.8 magnitude earthquake that hit Maule, Chile, in 2010, the Zemmouri-Boumerdes tsunami, Algeria, generated in 2003 by an earthquake of magnitude 6.8, and the recent tsunami generated almost a year ago by the earthquake of magnitude 7.0, which occurred near the Greek island of Samos. All the earthquakes located in the Mediterranean area that have activated the INGV CAT in recent years were also analyzed. This made it possible to evaluate the accuracy of the forecasting model over a wide range of magnitudes and types of the seismic event, from relatively small crustal earthquakes to larger events generated in subduction areas.
In order to be able to offer, in case of an event, an adequate response to citizens residing in coastal areas exposed to the risk of flooding from a tsunami, it is essential to combine the scientific evidence with political choices that are needed to link an alert level to a given probability, considering that each alert level, in turn, can correspond to certain coastal areas to be evacuated. The latter, in Italy, have been defined by ISPRA, INGV, and DPC, which are the components of the SiAM (“Sistema di Allertamento nazionale per i Maremoti generati da sisma”, the National Alert System for Tsunamis generated by earthquakes). Indeed, both missed and false alarms can generate significant socio-economical consequences. Given that both cases are due to the uncertainty in the prediction of hazardous events, the PTF aims at integrating the uncertainty itself into calculations.
This approach in the future may be useful also for the definition of new strategies of risk management, allowing, for example, the definition of different mitigation actions for specific issues based on the scientific information provided in real-time by the PTF such as, for example, the activation of procedures to safeguard industrial plants in cases of emergency.
Figure 1. The PTF integrates information derived from real-time monitoring with information on expected earthquakes in the area and, finally, with millions of numerical simulations of tsunami propagation pre-calculated thanks to modern supercomputers, providing estimates that may be updated over time, allowing a reduction of the uncertainty.
Figure 2. The quantifications produced by the PTF can be linked to the different alert levels of the early warning system, accounting for the actual uncertainties at the time of the estimate. This allows to define the alert level taking into account the potential number of false or missed alarms resulting from the unavoidable uncertainty that exists in the first minutes after the earthquake
The Seventeenth Session of the Intergovernmental Coordination Group for the North-eastern Atlantic, the Mediterranean and Connected Seas Tsunami Early Warning and Mitigation System (ICG/NEAMTWS-XVII) will not take place in person but online in November 2021 as a precaution to the COVID-19 Pandemic outbreak. More updates will be provided in preparation to the meeting in the coming weeks.