figure 1: Global distribution, updated in 2015, of areas covered by tsunami warning systems (TWS) as established by the Intergovernmental Coordination Group (ICG) of UNESCO's Intergovernmental Oceanographic Commission. The various competent bodies in the different areas are represented with the different colors: United States in dark red, Indian Ocean in blue, Pacific Ocean and the Caribbean Orange, Pacific Northwest in yellow and the northeastern Atlantic Ocean, Mediterranean Sea and related seas up to the Black Sea in dark green. The NEAMTH18 hazard model was developed on the latter area. --- Figures 1: Intergovernmental Coordination Groups global area of coverage map of the Tsunami Warning Systems, updated in 2015 by the Intergovernmental Oceanographic Commission of UNESCO. NEAMTWS (green). US NTWC, US national tsunami warning center (brownish red); IOTWS, Indian ocean tsunami warning and mitigation system (turquoise); PTWC, Pacific Tsunami Warning Center (orange); CARIBE-EWS: interim of PTWC and US NTWC; PTWS: Northwest Pacific Tsunami Advisory Center/Japan Meteorological Agency (yellow), PTWC, and US NTWC.
Figure 2: Examples of maximum flood height (MIH in metres) profiles along coasts with the highest hazard values in the NEAMTH18 model. The profile oriented north-south represents the coasts of the Gulf of Cadiz while the one oriented east-west represents the coasts of Cyrenaica. Both refer to the hazard model with an average return period of 2500 years and with different colors show the MIH for the average value (blue) and for the different percentiles of epistemic uncertainty (red: 50°; yellow: 16° and 84°; green: 2° and 98°). --- (Figure 2: Example profiles of the maximum inundation height (MIH; mean and the epistemic uncertainty represented by the 2nd, 16th, 50th, 84th, and 98th percentiles) along coastlines among those with the highest hazard of the NEAM Region. The two profiles span coast of the Gulf of Cadiz (N–S) and the Cyrenaica (E–W). Both profiles are with reference to the hazard model with the 2% probability of exceeding in 50 years (average return period of 2,475 years). The color scale in the map is as in (Figure 11. Topo bathymetry is from the ETOPO1 Global Relief Model (NOAA, 2009; Lover and Eakins, 2009).
Created the first hazard model for tsunamis generated by earthquakes in the NEAM area, the result of a European project coordinated by INGV
To quantify exposure to the tsunami risk affecting the Mediterranean coasts, in recent years an international team of researchers has created the first Earthquake-generated tsunami hazard model for the entire NEAM area (Northeast Atlantic Ocean, Mediterranean Sea and connected seas up to the Black Sea), denominated NEAMTHM18 (NEAM Tsunami Hazard Model 2018).
This model is the result of European project TSUMAPS-NEAM, coordinated by the National Institute of Geophysics and Volcanology (INGV) and financed by the European Civil Protection (DG-ECHO).
NEAMTHM18 is of particular interest for Italy since it has been used as a basis for civil protection planning on our coasts, as well as for the management of the evacuation of the population in response to a possible tsunami alert issued by SiAM, the national alert system for tsunamis generated by seismic events to which the INGV Tsunami Alert Center is a member (CAT-INGV).
In fact, on 18 March a modest tsunami was detected off the coast of Sardinia and the Balearic Islands, a consequence of the 6.2 magnitude earthquake recorded by the INGV National Seismic Network off the coast of Algeria.
This tsunami, by the way, was not the only one that occurred in the Mediterranean area. Only a few months earlier, on October 30, 2020, an earthquake measuring 7.0 with its epicenter in Samos in Greece, caused a tsunami in Samos and Izmir causing damage both in Greece and in Turkey where, moreover, one victim was recorded precisely because of the tidal wave.
“In the NEAMTHM18 model, the calculation of the tsunami hazard for the coasts under study was structured in four phases: the development of the probabilistic model on the occurrence of an earthquake; the numerical simulation of the generation and propagation of tsunami waves in the open sea; the statistical modeling of the flood probability of the analyzed coasts; the aggregation of the various stages aimed at quantifying the hazard curves", explains Roberto Basili, coordinator of the TSUMAPS-NEAM project for INGV and first author of the article published in the scientific journal 'Frontiers'.
The hazard curves provide an estimate of the probability that a tsunami of different heights will hit the coasts of the NEAM area in the future. The model is presented also expressing the uncertainty that characterizes these hazard estimates, with a sort of “error bar” for each of the estimated probability values.
"In fact, it should be remembered that the hazard values reported in the NEAMTHM18 model were quantified using a modeling technique that also took into account alternative data and approaches, following a structured decision-making process based on a protocol that made it possible to integrate in a transparent manner the opinions of experts from different disciplines, which are the expression of limitations of the available data and of different opinions within the scientific community"Basili adds. "The model therefore provides a 'family' of danger curves represented by the average value and by the various percentiles of the so-called 'epistemic uncertainty', i.e. linked to our level of knowledge of the phenomenon in question".
"The choices made by the DPC to formulate the indications for coastal planning took these uncertainties into account and consequently introduced 'safety factors'", continues the researcher. “Furthermore, as a planning reference, events with an average return time of 2.500 years have been identified, as has already been done by New Zealand. This choice reflects the fact that tsunamis are relatively rare events but have the potential to cause serious consequences. It should be noted that this average return time is greater than that of 475 years considered by seismic legislation, which refers to more frequent events".
In defining and calculating the hazard curves, 2.343 points of interest distributed along the NEAM coasts at an average distance of about 20 kilometers from each other were taken into consideration. Starting from these curves, it is possible to create probability maps for different levels of maximum flood height and hazard maps relating to the mean return period of the tsunami. Some examples, together with the necessary documentation, are reported on the model's website and can be consulted through a dedicated interactive tool.
From the analysis of the hazard curves it emerges that in the NEAM area flood values of a few meters are possible. “In particular, in 37% of the points where the hazard has been calculated in the Mediterranean Sea, an event exceeding a flood height of one meter could occur on average every 2.500 years. The points where even greater heights could occur more frequently are found on the Libyan, Egyptian, Cypriot and Greek coasts, as well as on the Italian coasts of the Ionian Sea. In the north-eastern Atlantic, the points of relatively high danger are located on the coasts of Mauritania and the Gulf of Cadiz. In the entire NEAM area, therefore also considering the coasts of the Black Sea and the Atlantic Ocean, the areas in which flood heights greater than one meter can occur in the same time interval correspond to 30% of the points analysed”, concludes Basili.
The NEAMTHM18 model therefore represents an important first step to initiate more detailed local assessments of the danger and consequent risks of tsunami-generated flooding in the NEAM area, having already acted as a starting point for contributing to the design of evacuation maps for the National tsunami alert.
Link to the article
#ingv #NEAM #NEAMTHM18 #tsunami #earthquake #Mediterranean
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NEAMTHM18, the first tsunami hazard model for the Northeast Atlantic, the Mediterranean Sea and connected seas is online
The first hazard model for tsunamis generated by earthquakes in the NEAM area, the result of a European project coordinated by INGV, has been realized
To quantify the tsunami risk for the Mediterranean coasts, an international team of researchers brought about the first earthquake-generated tsunami hazard model for the whole NEAM area (Northeast Atlantic Ocean, Mediterranean Sea, and connected seas up to the Black Sea).
This model, named NEAMTHM18 (NEAM Tsunami Hazard Model 2018), is the main product of the European Project TSUMAPS-NEAMcoordinated by the National Institute of Geophysics and Volcanology (INGV). NEAMTHM18 is of particular interest for Italy, because it has been used as a basis for Civil Protection planning along the coasts of the country, also to manage public evacuation in response to a possible tsunami alert issued by the “SiAM”, the National Warning System for Tsunamis generated by seismic events to which the Tsunami Alert Center of INGV (CAT-INGV) is part.
In fact, last March 18, offshore Sardinia and the Balearic Islands a moderate-sized tsunami was detected, due to the 6.2 magnitude earthquake recorded by the INGV National Seismic Network offshore the Algerian coast.
Moreover, this tsunami wasn't the only one that occurred in the Mediterranean area. Just a few months earlier, on October 30, 2020, a 7.0 magnitude earthquake with the epicenter in Samos, Greece, produced a tsunami in Samos and Izmir, causing damage both in Greece and Turkey where, moreover, a fatality was recorded due to the tsunami.
“In the NEAMTHM18 model, tsunami hazard calculation for the studied coasts was structured in four stages: the development of the probabilistic model of earthquake occurrence; the numerical simulation of tsunami wave generation and propagation in the open sea; the statistical modeling of the inundation probability; the aggregation of the different stages aimed at quantifying hazard curves”, Roberto Basili, Coordinator of the TSUMAPS-NEAM project for INGV and first author of the paper, explains.
The hazard curves provide estimates of the probability that a tsunami of different heights will strike the NEAM coast in the future. The model is presented by also expressing the uncertainty that characterizes these hazard estimates, with a sort of “error bar” for each of the estimated probability values.
“Indeed, it is worth recalling that the hazard values presented in the NEAMTHM18 model were quantified using a modeling technique that considered alternative data and approaches, following a formalized decision-making process based on a multiple-expert protocol. This procedure allowed us to transparently integrate the experts' opinions from different disciplines, which are the expression of limitations of available data and their different interpretations within the scientific community”, Basili adds. “Therefore, the model provides a family of hazard curves represented by the mean value and various percentiles of the so-called epistemic uncertainty, that is the uncertainty related to our level of knowledge of the phenomenon in question”.
“The choices made by DPC to formulate coastal planning guidance took these uncertainties into account and introduced 'safety factors' accordingly”, the researcher continues. “Besides, events with an average return time of 2,500 years were identified as a reference for planning, as New Zealand has already done. This choice reflects that tsunamis are relatively rare events with the potential to cause severe consequences. It should be noted that the average return period is greater than the 475-year average return period considered by the building codes for seismic hazard, which refers to more frequent events”. 2,343 points of interest (POIs) distributed along the NEAM coastline at an average spacing of about 20 kilometers were considered in the definition and calculation of hazard curves. Starting from these curves, maps of probability for different levels of maximum flood height (MIH) and hazard maps for different values of the average return period (ARP) can be made. Several examples, including the necessary documentation, can be found on the model website, accessible through a dedicated interactive tool.
Analysis of the hazard curves shows that inundation values of several meters are possible in the NEAM area. “Specifically, in 37% of the hazard locations in the Mediterranean Sea, an event exceeding a 1-meter inundation height could occur on average every 2,500 years. The points where even greater heights could be more frequent are on the Libyan, Egyptian, Cypriot and Greek coasts, as well as on the Italian coasts of the Ionian Sea. In the northeast Atlantic, the points characterized by a relatively high hazard are located on the coasts of Mauritania and the Gulf of Cadiz. In the whole NEAM area, also considering the coasts of the Black Sea and the Atlantic Ocean, in 30% of the analyzed points we can have in the same time interval inundation heights higher than 1 meter”, Basili explains.
While NEAMTHM18 represents the springboard for starting more detailed local hazard assessments and subsequent risk analyzes for tsunami-generated inundations in the NEAM area, it has already been used as a basis to help design evacuation maps for the National Tsunami Warning System.
Link to the article
#ingv #NEAM #NEAMTHM18 #tsunami #earthquake #Mediterranean
To quantify exposure to the tsunami risk affecting the Mediterranean coasts, in recent years an international team of researchers has created the first Earthquake-generated tsunami hazard model for the entire NEAM area (Northeast Atlantic Ocean, Mediterranean Sea and connected seas up to the Black Sea), denominated NEAMTHM18 (NEAM Tsunami Hazard Model 2018).
This model is the result of European project TSUMAPS-NEAM, coordinated by the National Institute of Geophysics and Volcanology (INGV) and financed by the European Civil Protection (DG-ECHO).
NEAMTHM18 is of particular interest for Italy since it has been used as a basis for civil protection planning on our coasts, as well as for the management of the evacuation of the population in response to a possible tsunami alert issued by SiAM, the national alert system for tsunamis generated by seismic events to which the INGV Tsunami Alert Center is a member (CAT-INGV).
In fact, on 18 March a modest tsunami was detected off the coast of Sardinia and the Balearic Islands, a consequence of the 6.2 magnitude earthquake recorded by the INGV National Seismic Network off the coast of Algeria.
This tsunami, by the way, was not the only one that occurred in the Mediterranean area. Only a few months earlier, on October 30, 2020, an earthquake measuring 7.0 with its epicenter in Samos in Greece, caused a tsunami in Samos and Izmir causing damage both in Greece and in Turkey where, moreover, one victim was recorded precisely because of the tidal wave.
“In the NEAMTHM18 model, the calculation of the tsunami hazard for the coasts under study was structured in four phases: the development of the probabilistic model on the occurrence of an earthquake; the numerical simulation of the generation and propagation of tsunami waves in the open sea; the statistical modeling of the flood probability of the analyzed coasts; the aggregation of the various stages aimed at quantifying the hazard curves", explains Roberto Basili, coordinator of the TSUMAPS-NEAM project for INGV and first author of the article published in the scientific journal 'Frontiers'.
The hazard curves provide an estimate of the probability that a tsunami of different heights will hit the coasts of the NEAM area in the future. The model is presented also expressing the uncertainty that characterizes these hazard estimates, with a sort of “error bar” for each of the estimated probability values.
"In fact, it should be remembered that the hazard values reported in the NEAMTHM18 model were quantified using a modeling technique that also took into account alternative data and approaches, following a structured decision-making process based on a protocol that made it possible to integrate in a transparent manner the opinions of experts from different disciplines, which are the expression of limitations of the available data and of different opinions within the scientific community"Basili adds. "The model therefore provides a 'family' of danger curves represented by the average value and by the various percentiles of the so-called 'epistemic uncertainty', i.e. linked to our level of knowledge of the phenomenon in question".
"The choices made by the DPC to formulate the indications for coastal planning took these uncertainties into account and consequently introduced 'safety factors'", continues the researcher. “Furthermore, as a planning reference, events with an average return time of 2.500 years have been identified, as has already been done by New Zealand. This choice reflects the fact that tsunamis are relatively rare events but have the potential to cause serious consequences. It should be noted that this average return time is greater than that of 475 years considered by seismic legislation, which refers to more frequent events".
In defining and calculating the hazard curves, 2.343 points of interest distributed along the NEAM coasts at an average distance of about 20 kilometers from each other were taken into consideration. Starting from these curves, it is possible to create probability maps for different levels of maximum flood height and hazard maps relating to the mean return period of the tsunami. Some examples, together with the necessary documentation, are reported on the model's website and can be consulted through a dedicated interactive tool.
From the analysis of the hazard curves it emerges that in the NEAM area flood values of a few meters are possible. “In particular, in 37% of the points where the hazard has been calculated in the Mediterranean Sea, an event exceeding a flood height of one meter could occur on average every 2.500 years. The points where even greater heights could occur more frequently are found on the Libyan, Egyptian, Cypriot and Greek coasts, as well as on the Italian coasts of the Ionian Sea. In the north-eastern Atlantic, the points of relatively high danger are located on the coasts of Mauritania and the Gulf of Cadiz. In the entire NEAM area, therefore also considering the coasts of the Black Sea and the Atlantic Ocean, the areas in which flood heights greater than one meter can occur in the same time interval correspond to 30% of the points analysed”, concludes Basili.
The NEAMTHM18 model therefore represents an important first step to initiate more detailed local assessments of the danger and consequent risks of tsunami-generated flooding in the NEAM area, having already acted as a starting point for contributing to the design of evacuation maps for the National tsunami alert.
Link to the article
#ingv #NEAM #NEAMTHM18 #tsunami #earthquake #Mediterranean
---
NEAMTHM18, the first tsunami hazard model for the Northeast Atlantic, the Mediterranean Sea and connected seas is online
The first hazard model for tsunamis generated by earthquakes in the NEAM area, the result of a European project coordinated by INGV, has been realized
To quantify the tsunami risk for the Mediterranean coasts, an international team of researchers brought about the first earthquake-generated tsunami hazard model for the whole NEAM area (Northeast Atlantic Ocean, Mediterranean Sea, and connected seas up to the Black Sea).
This model, named NEAMTHM18 (NEAM Tsunami Hazard Model 2018), is the main product of the European Project TSUMAPS-NEAMcoordinated by the National Institute of Geophysics and Volcanology (INGV). NEAMTHM18 is of particular interest for Italy, because it has been used as a basis for Civil Protection planning along the coasts of the country, also to manage public evacuation in response to a possible tsunami alert issued by the “SiAM”, the National Warning System for Tsunamis generated by seismic events to which the Tsunami Alert Center of INGV (CAT-INGV) is part.
In fact, last March 18, offshore Sardinia and the Balearic Islands a moderate-sized tsunami was detected, due to the 6.2 magnitude earthquake recorded by the INGV National Seismic Network offshore the Algerian coast.
Moreover, this tsunami wasn't the only one that occurred in the Mediterranean area. Just a few months earlier, on October 30, 2020, a 7.0 magnitude earthquake with the epicenter in Samos, Greece, produced a tsunami in Samos and Izmir, causing damage both in Greece and Turkey where, moreover, a fatality was recorded due to the tsunami.
“In the NEAMTHM18 model, tsunami hazard calculation for the studied coasts was structured in four stages: the development of the probabilistic model of earthquake occurrence; the numerical simulation of tsunami wave generation and propagation in the open sea; the statistical modeling of the inundation probability; the aggregation of the different stages aimed at quantifying hazard curves”, Roberto Basili, Coordinator of the TSUMAPS-NEAM project for INGV and first author of the paper, explains.
The hazard curves provide estimates of the probability that a tsunami of different heights will strike the NEAM coast in the future. The model is presented by also expressing the uncertainty that characterizes these hazard estimates, with a sort of “error bar” for each of the estimated probability values.
“Indeed, it is worth recalling that the hazard values presented in the NEAMTHM18 model were quantified using a modeling technique that considered alternative data and approaches, following a formalized decision-making process based on a multiple-expert protocol. This procedure allowed us to transparently integrate the experts' opinions from different disciplines, which are the expression of limitations of available data and their different interpretations within the scientific community”, Basili adds. “Therefore, the model provides a family of hazard curves represented by the mean value and various percentiles of the so-called epistemic uncertainty, that is the uncertainty related to our level of knowledge of the phenomenon in question”.
“The choices made by DPC to formulate coastal planning guidance took these uncertainties into account and introduced 'safety factors' accordingly”, the researcher continues. “Besides, events with an average return time of 2,500 years were identified as a reference for planning, as New Zealand has already done. This choice reflects that tsunamis are relatively rare events with the potential to cause severe consequences. It should be noted that the average return period is greater than the 475-year average return period considered by the building codes for seismic hazard, which refers to more frequent events”. 2,343 points of interest (POIs) distributed along the NEAM coastline at an average spacing of about 20 kilometers were considered in the definition and calculation of hazard curves. Starting from these curves, maps of probability for different levels of maximum flood height (MIH) and hazard maps for different values of the average return period (ARP) can be made. Several examples, including the necessary documentation, can be found on the model website, accessible through a dedicated interactive tool.
Analysis of the hazard curves shows that inundation values of several meters are possible in the NEAM area. “Specifically, in 37% of the hazard locations in the Mediterranean Sea, an event exceeding a 1-meter inundation height could occur on average every 2,500 years. The points where even greater heights could be more frequent are on the Libyan, Egyptian, Cypriot and Greek coasts, as well as on the Italian coasts of the Ionian Sea. In the northeast Atlantic, the points characterized by a relatively high hazard are located on the coasts of Mauritania and the Gulf of Cadiz. In the whole NEAM area, also considering the coasts of the Black Sea and the Atlantic Ocean, in 30% of the analyzed points we can have in the same time interval inundation heights higher than 1 meter”, Basili explains.
While NEAMTHM18 represents the springboard for starting more detailed local hazard assessments and subsequent risk analyzes for tsunami-generated inundations in the NEAM area, it has already been used as a basis to help design evacuation maps for the National Tsunami Warning System.
Link to the article
#ingv #NEAM #NEAMTHM18 #tsunami #earthquake #Mediterranean