Tsunami and Storm Surge Modelling in the North East ...

Tsunami and Storm Surge Modelling in the North East Atlantic Numerical analysis using hydrodynamic models

Ricardo Tavares da Costa Alessandro Annunziato 2014

Report EUR 26878 EN

European Commission Joint Research Centre Institute for the Protection and Security of the Citizen Contact information Alessandro Annunziato Address: European Commission, Joint Research Centre (JRC), Institute for the Protection and Security of the Citizen (IPSC), Global Security and Crisis Management Unit, Via Enrico Fermi 2749, 21027 Ispra VA, Italy E-mail: [email protected] Tel.: +(39) 0332 78-9519 https://ec.europa.eu/jrc Legal Notice This publication is a Science and Policy Report by the Joint Research Centre, the European Commission’s in-house science service. It aims to provide evidence-based scientific support to the European policy-making process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use, which might be made of this publication. All images © European Union 2014 The geographic borders are purely a graphical representation and are only intended to be indicative. The boundaries do not necessarily reflect the official position of the European Commission. JRC91692 EUR 26878 EN ISBN 978-92-79-43548-5 (PDF) ISSN 1831-9424 (online) doi:10.2788/18260 Luxembourg: Publications Office of the European Union, 2014 © European Union, 2014 Reproduction is authorised provided the source is acknowledged.

Abstract This report presents the numerical modelling outcomes for selected historical events using the JRC-SWAN, HyFlux2 and SELFE models, namely the 1755 Great Lisbon Earthquake, the 1969 Horseshoe Abyssal Plain Earthquake and the 2010 Xynthia Storm. This research was carried out in the European Crisis Management Laboratory at the European Commission Joint Research Centre, Institute for the Protection and Security of the Citizen, Global Security and Crisis Management Unit, Crisis Monitoring and Response Technologies, in the scope of the project Natural Disaster Detection, Monitoring and Alerting for Humanitarian and Civil Protection Communities.

EUROPEAN COMMISSION JOINT RESEARCH CENTRE Institute for the Protection and Security of the Citizen Global Security and Crisis Management Unit

Full Name of Scientific and Policy Report:

Tsunami and Storm Surge Modelling in the North East Atlantic

This report presents the numerical modelling outcomes for selected historical events using the JRCSWAN, HyFlux2 and SELFE models, namely the 1755 Great Lisbon Earthquake, the 1969 Horseshoe Abyssal Plain Earthquake and the 2010 Xynthia Storm. This research was carried out in the European Crisis Management Laboratory at the European Commission Joint Research Centre, Institute for the Protection and Security of the Citizen, Global Security and Crisis Management Unit, Crisis Monitoring and Response Technologies, in the scope of the project Natural Disaster Detection, Monitoring and Alerting for Humanitarian and Civil Protection Communities. Institutional Action Acronym: Pubsy Sub-category:

CRITECH

2.2.a Scientific and policy reports

Name

Date

Reviewed by the Project Leader

Alessandro Annunziato

26/09/2014

Approved by the Action Leader

Alessandro Annunziato

26/09/2014

Signature

Table of Contents 1 Executive Summary ............................................................................................................................................... 5 2 Introduction ................................................................................................................................................................ 6 2.1

Tsunami Area of Study ...........................................................................................................................................................7

2.2

Storm Surge Area of Study ...................................................................................................................................................7

2.3

The 1755 Great Lisbon Earthquake .................................................................................................................................7

2.4

The 1969 Horseshoe Abyssal Plain Earthquake ........................................................................................................7

2.5

The 2010 Xynthia Storm........................................................................................................................................................7

3 Tsunami Analysis .................................................................................................................................................... 8 3.1

JRC Numerical Calculations ..................................................................................................................................................8

3.1.1 The 1755 Great Lisbon Earthquake ............................................................................................................................8 3.1.2 The 1969 Horseshoe Abyssal Plain Earthquake ................................................................................................18 3.2

JRC Tsunami Scenario Database ....................................................................................................................................23

3.3

SELFE Numerical Calculations..........................................................................................................................................25

3.3.1 The 1969 Horseshoe Abyssal Plain Earthquake ................................................................................................27 3.3.2 The 1755 Great Lisbon Earthquake .........................................................................................................................30 3.4

JRC-SELFE Benchmark .........................................................................................................................................................33

4 Storm Surge Analysis ........................................................................................................................................ 35 5 Conclusion ............................................................................................................................................................... 40 6 Acknowledgements ............................................................................................................................................. 40 7 References............................................................................................................................................................... 41

1 Executive Summary This report presents the numerical modelling outcomes for selected historical events using the JRCSWAN, HyFlux2 and SELFE models, namely the 1755 Great Lisbon Earthquake, the 1969 Horseshoe Abyssal Plain Earthquake and the 2010 Xynthia Storm. The main objectives of this study were to test a high-resolution state-of-the-art numerical model for its ability to estimate tsunami and storm surge propagation and inundation across scales, to evaluate its potential to improve or complement the current modelling framework in place and to evaluate its operationalisation viability. Furthermore, an analysis of the considered case studies was developed for future reference. Although SELFE produced promising results for tsunami and storm surge modelling, even at a preliminary stage, its suitability for near real-time operations is still under investigation. New findings on the selected case studies were realised and are here discussed.

5

2 Introduction Numerical investigations for selected historical events presented in this report were conducted using the European Commission Joint Research Centre (JRC) Tsunami Assessment Modelling System and Analysis Tool (Annunziato, 2007), hereafter referred to as the JRC tsunami system, and the SELFE (Zhang and Baptista, 2008) numerical model. The JRC tsunami system employs two computationally inexpensive schemes, up to second order accuracy, the JRC-SWAN (based on Mader, 2004) and the HyFlux2 (Franchello, 2010). Both schemes use structured meshes to solve through finite-difference and finite-volume formulations the two-dimensional NavierStokes and shallow water equations. On the other hand, the SELFE model (parallel version 3.1.dc) due to its finite-element/volume formulation allows more freedom for higher orders of accuracy. SELFE uses a high-resolution triangular unstructured mesh to solve the three-dimensional Navier-Stokes and shallow water equations. This renders this scheme more flexible in handling complex geometries and properties across scales, hardly resolved with inexpensive homogeneous spatial resolutions. We investigate whether the JRC tsunami system could benefit from this or other models alike. The events selected for study represent two types of natural hazards, relevant in the field of Disaster Detection, Monitoring and Alerting, and in line with developments of the Global Disaster Alert and Coordination System cooperation framework (GDACS, http://www.gdacs.org/). GDACS combines different web-based disaster information management systems with the aim to alert the international community in case of major sudden-onset disasters and to facilitate the coordination of international response during relief. A tsunami, usually resulting from a seismic disturbance, is a large sudden displacement of water that can have devastating consequences if it reaches the coast. GDACS incorporates the JRC tsunami system to estimate wave propagation, travel times, inundation and impact in case of a tsunami event. The system initialises with the estimation of the deformation of the earth’s crust, due to an earthquake, from parameters provided by different earthquake information centres. This estimation is then used to calculate the resulting water displacement and run the hydrodynamic models that will provide data in a timely manner for informed decision-making. In contrast, a storm surge is an abnormal rise of water caused by storm wind and pressure forces. This high-energy phenomenon poses serious coastal risks. The JRC is currently testing a storm surge system. Devastation caused by recent and historical events, such as the ones mentioned in this report, point out the need to adopt long-term strategies for emergency preparedness and risk reduction, for example: the implementation of early warning systems, structural measures and the update of building and refurbishment codes. For the tsunami analysis part of this report two major events were chosen, the 1969 Horseshoe Abyssal Plain tsunamigenic earthquake, a well-constrained case to adjust the model, and the 1755 Great Lisbon earthquake, a high-magnitude, high–impact and complex case. Both major events were located off the southwestern coast of Portugal, in the North-East Atlantic Ocean. For the storm surge analysis, the Storm Xynthia that occurred between February and March 2010 was chosen. Its centre passed off the coast of Portugal, made landfall in the northeastern part of Spain, crossed the Bay of Biscay and made landfall again in France.

6

2.1 Tsunami Area of Study The selected area of study comprises the region southwest of Portugal and Gulf of Cadiz. Active faults in this region are capable of generating large and destructive tsunamigenic earthquakes such as the 1755 Great Lisbon earthquake and the 1969 Horseshoe Plain earthquake, posing a hazard to neighbouring countries. Seismicity is dominated by shallow to intermediate depth events with strike-slip and reverseoblique focal mechanisms (Cunha et al., 2012). The northeast-southwest striking thrust system comprises the Horseshoe, Marquês de Pombal, and Tagus Abyssal Plain faults and the Gorringe Bank (Duarte et al., 2013), a feature whose summit reaches 25 m below sea level.

Figure 1: Historical seismicity map of the region southwest of Portugal and vicinity, obtained with the JRC Tsunami Analysis Tool.

2.2 Storm Surge Area of Study The selected area of study comprises the North-East Atlantic region. This region is characterised by fluctuations of atmospheric pressure at sea level, between the Icelandic low and the Azores high-pressure systems, which may influence the strength and direction of storms across Europe. It is the region with the deepest observed central pressures of extratropical cyclones and there is evidence for an increase in number and intensity of storms (Emanuel, 2005).

2.3 The 1755 Great Lisbon Earthquake The 1755 Great Lisbon Earthquake occurred, according to historical records, on the 1st of November 1755 around 09:30:00 UTC. It is characterised as a high-magnitude high-impact tsunamigenic event that produced the largest tsunami known to date in the southwestern part of Europe. Its epicentre location is still uncertain, but possibly located in the Horseshoe Abyssal Plain Thrust, off the southwestern coast of Portugal, according to Matias et al. (2013). Estimated magnitude for this event is approx. Mw 8.7, with a depth to the top of the fault of approx. 5 km.

2.4 The 1969 Horseshoe Abyssal Plain Earthquake The 1969 Horseshoe Abyssal Plain Earthquake occurred on the 28th of February around 02:40:33 UTC. It is characterised as a tsunamigenic event with a well-constrained focal mechanism and epicentre, with location 36.010º latitude and -10.570º longitude, off the southwestern coast of Portugal, according to Fukao (1973). The estimated magnitude for this event is approx. Mw 7.9, with a depth of approx. 33 km.

2.5 The 2010 Xynthia Storm Storm Xynthia, the most destructive in the winter of 2009/2010 and whose genesis, development and path were uncommon, arose from an initially low-pressure system formed south of Azores, Portugal, on the 25th of February 2010. Xynthia followed a southwest-northeast track moving towards France, passing over Portugal, Spain and the Bay of Biscay, intensifying rapidly with devastating consequences. The hurricane made landfall in France in the early hours of the 28th of February. Extreme sea levels were recorded in the coasts of Portugal, Spain and France. 7

3 Tsunami Analysis The tsunamis caused by the 1755 Great Lisbon Earthquake and the 1969 Horseshoe Abyssal Plain Earthquake, offshore of Portugal, were simulated based on different calculation scenarios. The JRC tsunami system was used to perform the hydrodynamic simulations of tsunami propagation and water level fluctuations. Three levels of detail were considered for each calculation, a coarse and medium resolution run using the JRC-SWAN model, corresponding to a structured mesh with cell sizes of 2 arcminutes (approx. 0.032º or 3600 m) and 1 arc-minute (approx. 0.016º or 1800 m), respectively, and a finer resolution run using the HyFlux2 model, corresponding to a structured mesh with cell size 0.25 arcminutes (approx. 0.004º or 450 m). Furthermore, the JRC Tsunami Database was assessed for comprehensiveness, determining if matching scenarios, to the ones developed in the scope of this report, could be found. Finally, for each event a representative scenario was selected and further detailed simulations were performed using the SELFE model. The SELFE model was benchmarked against the SWAN/HyFlux2 suite.

3.1 JRC Numerical Calculations Available published earthquake source parameters allowed the preparation of 21 calculation scenarios for the 1755 Great Lisbon Earthquake and 3 scenarios for the 1969 Horseshoe Abyssal Plain Earthquake. For the multi-fault rupture earthquakes the overall magnitude was estimated using the following equations in SI units (Hanks and Kanamori, 1979, Gica et al., 2008): M0,i = µd0,i Si

(Eq. 1)

Si = Li Wi

(Eq. 2)

Where M0 is the fault’s segment seismic moment, i is the fault’s segment index, μ is the earth’s rigidity (assumed 4.0 x 1010 Pa), d0 the fault’s segment average slip (m) and S is the fault’s segment area (m2). Where L is the fault’s segment length (m) and W the fault’s segment width (m). 2

(Eq. 3)

Mw = log�∑ni=1 M0,i � − 6.1 3

Where MW is the fault’s overall moment magnitude and n is the number of fault segments. 3.1.1 The 1755 Great Lisbon Earthquake A summary of the specific earthquake parameters and focal mechanism solutions used for the 1755 Great Lisbon Earthquake is presented in Table 1 and Figure 2. Scenarios 1, 5, 6, 16 and 21 correspond to multi-fault rupture scenarios. Figures 3 to 6 provide a comparison of the earthquake parameters. The magnitude, for each calculation scenario, ranges between 8 and 9 Mw, with the lowest truncated value being 8.1, scenario 12, and the highest being 8.7, scenarios 5, 13 and 21. Depth is higher for scenarios 8 to 12, ranging from 25 to 50 km deep; Remaining scenarios present shallower depths, starting at 5 km and going up to 15 km. The slip or displacement along the fault does not vary significantly; values are distributed around 10 m, except for scenario 1 that presents the highest slip fixed at 20 m. Scenarios 9 to 12, 17 and 20 represent the smallest fault rupture areas ranging from 5,500 to 7,200 km2; scenarios 13 and 19 have the largest areas of 27,000 and 25,000 km2, respectively. For the multifault scenarios, values for the summed areas of each segment are given as follows: scenario 1, 11,055 km2; scenario 5, 36,554 km2; scenario 6, 13,239 km2; scenario 16, 25,200 km2; and, scenario 21, 31,700 km2. Scenario 1 and 6 are the multi-fault scenarios with the smallest areas of 11,100 and 13,200 km2, respectively, and scenario 5 and 21 are the multi-fault scenarios with the largest areas of 37,000 and 32,200 km2, respectively.

8

MPF+GB

2 3 4

JRC1/12668 JRC1/12669 JRC1/12670

HF HF GB

5

Lisbon_1755/ scenarios/5

GCWF MF

6


MPF+PSF

7 8 9 10 11 12 13 14 15

JRC1/12671 JRC1/12672 JRC1/12673 JRC1/12675 JRC1/12676 JRC1/12677 JRC1/12678 JRC1/12679 JRC1/12680

GB GB GB HF MPF PBF GCWF HF MPF

16


HF+MPF

17 18 19 20

JRC1/12681 JRC1/12683 JRC1/12684 JRC1/12685

MPF HF HF MPF

21


HF+MPF

-9.890 1 -11.250 1 -9.913 -11.467 -11.450 -8.930 -8.200 -7.480 -9.790 -10.100 -9.610 -9.780 -10.270 -9.600 -10.580 -10.270 -10.270 -11.281 -10.000 -10.067 -8.664 -9.329 -9.913 1 -9.890 1 -9.913 1 -9.890 1 -9.890 -9.913 -9.913 1 -9.890 1 -9.913 1 -9.890 1

8.5 8.5 8.5 8.4 8.7

8.4

8.5 8.5 8.5 8.5 8.5 8.3 8.4 8.5 8.5 8.6 8.5 8.5 8.5 8.5 8.6

5.0 5.0 5.0 5.0 8.0 6.5 9.5 15.4 18.0 5.0 18.0 11.0 9.0 11.0 7.0 5.0 50.0 25.0 25.0 25.0 25.0 12.0 5.0 5.0 5.0 5.0 4.0 4.0 5.0 5.0 5.0 5.0

Strike, ϕ (Dec. Deg.)

Dip, δ (Dec. Deg.)

Rake, λ (Dec. Deg.)

21.7 70.0 42.1 345.0 60.0 349.0 349.0 349.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 57.0 57.0 233.0 222.1 200.0 266.3 346.3 235.0 23.0 235.0 23.0 20.0 42.1 235.0 23.0 235.0 23.0

24.0 45.0 35.0 40.0 40.0 2.5 5.0 7.5 0.0 24.0 0.0 24.0 2.5 24.0 2.5 40.0 40.0 25.0 25.0 25.0 25.0 6.0 45.0 45.0 45.0 45.0 35.0 35.0 45.0 30.0 45.0 30.0

90.0 90.0 90.0 90.0 90.0 79.0 79.0 79.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0

105.00 96.00 165.00 200.00 200.00 162.02 174.02 198.02 55.66 55.66 37.15 37.15 37.15 55.66 55.66 200.00 200.00 137.00 106.00 86.00 100.00 133.00 150.00 60.00 150.00 60.00 129.00 165.00 175.00 60.00 175.00 60.00

55.00 55.00 70.00 80.00 80.00 68.32 68.33 68.65 40.00 31.96 20.00 17.21 46.43 17.21 92.86 80.00 80.00 60.00 70.00 70.00 55.00 200.00 120.00 120.00 120.00 120.00 70.00 70.00 140.00 120.00 140.00 120.00

Fault Rupture Area 2, S (103 km2) 5.8 5.3 12.0 16.0 16.0 11.0 12.0 14.0 2.2 1.8 0.7 0.6 1.7 1.0 5.2 16.0 16.0 8.2 7.4 6.0 5.5 27.0 18.0 7.2 18.0 7.2 9.0 12.0 25.0 7.2 25.0 7.2

Fault Slip, d (m)

36.574 1 36.450 1 35.796 36.015 36.940 35.300 35.470 35.690 36.660 36.750 37.050 37.100 37.240 37.490 37.780 36.010 36.010 36.948 36.133 36.895 36.105 34.833 35.796 1 36.574 1 35.796 1 36.574 1 36.574 35.796 35.796 1 36.574 1 35.796 1 36.574 1

Depth (km)

Longitude (Dec. Deg.)

Fault Width, W (km)

Lisbon_1755/scenarios/1

Latitude (Dec. Deg.)

Plane

Fault Length, L (km)

1

Epicentre

Magnitude 2, Mw

JRC Scenario ID

Structural Feature

Scenario No.

Table 1: Calculation scenarios based on specific earthquake parameters and focal mechanism solutions for the 1755 Great Lisbon Earthquake.

20.0 20.0 15.0 13.1 13.1 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 12.1 12.1 8.3 10.7 8.0 7.2 11.1 10.0 10.0 10.0 10.0 8.0 10.7 10.0 10.0 10.0 10.0

Ref.

BAP1 BAP2 BAR

GRA

JOH

LIM

MAT OMI RIB

Values for an earth’s rigidity of 4.0 x 1010 Pa Structural Features: GB – Gorringe Bank; GCWF – Gulf of Cadiz Wedge Fault; HF – Horseshoe Abyssal Plain Thrust Fault; MPF – Marquês de Pombal Fault; PBF – Portimão Bank Fault; PSF – Pereira de Sousa Fault; MF – Multi-Fault References: BAP1 – Baptista et al., 2003; BAP2 – Baptista et al., 2011; BAR – Barkan et al., 2009; GRA – Grandin et al., 2007; JOH – Johnston, 1996; LIM – Lima et al., 2010; MAT – Matias et al., 2013; OMI – Omira et al., 2011; RIB – Ribeiro et al., 2006 1 assumed value 2 calculated value

9

Scenario 1 MPF Segment 1

Scenario 1 GB Segment 2

Scenario 2 HF

Scenario 3 HF

Scenario 4 GB

Scenario 5 GCWF Segment 1



Scenario 6 HF Segments 1, 3

Scenario 6 HF Segments 2, 4, 6

Scenario 6 HF Segments 5, 7

Scenarios 7, 8 GB

Scenario 12 PBF

Scenario 13 GCWF

Scenario 9 GB

Scenarios 14, 19 HF Scenarios 16, 21 HF Segment 1

Scenario 10 HF

Scenario 15 MPF Scenario 16 HF Segment 2

Scenario 11 MPF

Scenario 17 MPF

Scenario 20 MPF Scenario 21 MPF Segment 2

Scenario 18 HF

Structural Features: GB – Gorringe Bank; GCWF – Gulf of Cadiz Wedge Fault; HF – Horseshoe Abyssal Plain Thrust Fault; MPF – Marquês de Pombal Fault; PBF – Portimão Bank Fault; PSF – Pereira de Sousa Fault; MF – Multi-Fault

Figure 2: Focal mechanism solutions for each scenario used in the analysis of the 1755 Great Lisbon Earthquake.

10

21 HF+MPF MF

20 MPF

19 HF

18 HF

17 MPF

16 HF+MPF MF

15 MPF

14 HF

13 GCWF

12 PBF

11 MPF

10 HF

9 GoR

8 GoR

7 GoR

6 MPF+PSF MF

5 GCWF MF

4 GoR

3 HF

2 HF

1 MPF+GoR MF

Magnitude Mw

8.8 8.7 8.6 8.5 8.4 8.3 8.2 8.1 8.0


50.0 45.0 40.0 35.0 30.0 25.0 20.0 15.0 10.0 5.0 0.0 1.1 MPF+GoR 1.2 MPF+GoR 2 HF 3 HF 4 GoR 5.1 GCWF 5.2 GCWF 5.3 GCWF 6.1 MPF+PSF 6.2 MPF+PSF 6.3 MPF+PSF 6.4 MPF+PSF 6.5 MPF+PSF 6.6 MPF+PSF 6.7 MPF+PSF 7 GoR 8 GoR 9 GoR 10 HF 11 MPF 12 PBF 13 GCWF 14 HF 15 MPF 16.1 HF+MPF 16.2 HF+MPF 17 MPF 18 HF 19 HF 20 MPF 21.1 HF+MPF 21.2 HF+MPF

Depth (km)

Figure 3: Magnitude for each 1755 Great Lisbon Earthquake scenario.


20.0 18.0 16.0 14.0 12.0 10.0 8.0 6.0 4.0 2.0 0.0 1.1 MPF+GoR 1.2 MPF+GoR 2 HF 3 HF 4 GoR 5.1 GCWF 5.2 GCWF 5.3 GCWF 6.1 MPF+PSF 6.2 MPF+PSF 6.3 MPF+PSF 6.4 MPF+PSF 6.5 MPF+PSF 6.6 MPF+PSF 6.7 MPF+PSF 7 GoR 8 GoR 9 GoR 10 HF 11 MPF 12 PBF 13 GCWF 14 HF 15 MPF 16.1 HF+MPF 16.2 HF+MPF 17 MPF 18 HF 19 HF 20 MPF 21.1 HF+MPF 21.2 HF+MPF

Fault Slip, d (m)

Figure 4: Depth for each 1755 Great Lisbon Earthquake scenario.


Figure 5: Fault slip for each 1755 Great Lisbon Earthquake scenario.

11

21…

20 MPF

Segment 7

19 HF

18 HF

17 MPF

Segment 6

16…

15 MPF

14 HF

Segment 5

13 GCWF

12 PBF

11 MPF

10 HF

9 GoR

Segment 4

8 GoR

Segment 3

7 GoR

6 MPF+PSF…

5 GCWF MF

4 GoR

Segment 2

3 HF

2 HF

Segment 1

1…

Fault Rupture Area (km^2)

40000 38000 36000 34000 32000 30000 28000 26000 24000 22000 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0


Figure 6: Fault rupture area for each 1755 Great Lisbon Earthquake scenario.

Each calculation, relative to a specific scenario, estimated a different maximum wave amplitudes map for the 1755 Great Lisbon Earthquake. Figure 7 presents the spatial distribution of the maximum estimated wave amplitudes for each scenario considered in this analysis.

Scenario 1 MPF+GB MF

Scenario 2 HF

Scenario 3 HF

Scenario 4 GB

Scenario 5 GCWF MF

Scenario 6 MPF+PSF MF

Scenario 7 GB

Scenario 8 GB

Scenario 9 GB

12

Scenario 10 HF

Scenario 11 MPF

Scenario 12 PBF

Scenario 13 GCWF

Scenario 14 HF

Scenario 15 MPF

Scenario 16 HF+MPF MF

Scenario 17 MPF

Scenario 18 HF

Scenario 19 HF

Scenario 20 MPF

Scenario 21 HF+MPF MF

Structural Features: GB – Gorringe Bank; GCWF – Gulf of Cadiz Wedge Fault; HF – Horseshoe Abyssal Plain Thrust Fault; MPF – Marquês de Pombal Fault; PBF – Portimão Bank Fault; PSF – Pereira de Sousa Fault; MF – Multi-Fault Colour range from 2 m, yellow, to -2 m, cyan

Figure 7: Spatial distribution of maximum estimated wave amplitudes for each scenario in the analysis of the 1755 Great Lisbon Earthquake.

The maximum estimated wave amplitudes for scenarios 5, 6 and 12 to 13 extend to a smaller area than the remaining ones. These scenarios present significantly different earthquake details and focal mechanism solutions, except for the slip along the fault. The maximum estimated wave heights for scenarios 1 to 4 and scenario 7 extend to a significant larger area than the remaining ones. These scenarios, located very close to each other, present a combination of a relatively large fault area, shallow depth, and high displacement. Scenarios 5, 6, 9, 11, 12 and 13 present the smallest maximum estimated wave heights extent. 13

Table 2 summarizes, for each calculation scenario, the values and specific locations for which the maximum wave height was estimated. A travel time range is provided for each case. Medium resolution runs for the multi-fault scenarios and finer resolution runs for all scenarios were not produced due to resource constrains. Scenario 1 presents the highest maximum estimated wave height for the coarse resolution, with 6.65 m. Scenarios 2 and 3 present the highest maximum estimated wave heights for the medium resolution, with 7.22 m. Scenario 9 presents the overall lowest maximum estimated wave height, with 1.63 m (coarse resolution) and 2.95 m (medium resolution). In the coarse resolution, scenarios 1, 3, 4, 6, 9, 11, 12, 14, 15, 17, 18 and 20 present the maximum estimated wave height location in Portugal with scenario 4 being the only case in which the maximum estimated wave height location is not in the south of the country, Algarve region, but in the Zona Oeste region. The remaining scenarios estimate the maximum wave height in the coastal area of Morocco, locations extending from Tangier to El Jadida, scenarios 2, 5, 7, 8, 10, 13, 16, 19 and 21. No scenario estimated the maximum wave height in Spain in the coarse resolution. Location and orientation of the earthquake’s fault as well as local features are determinant factors affecting this outcome. For the medium resolution, scenarios 3, 9, 11, 12, 15, 17 and 20 present the maximum estimated wave height location in Portugal, Algarve region. For scenarios 2, 7, 8, 10, 13, 14 and 18 the maximum estimated wave height location is situated in the Moroccan coast. For scenarios 4 and 19 the maximum estimated wave height location is situated in the Canary Islands, Spain. In terms of travel times, for the coarse resolution, scenarios 1, 6, 11 and 20 present the lowest values of 2 min and scenario 10 the highest value of 44 min. For the medium resolution, scenarios 15, 17 and 20 present the lowest values of 12 min and scenario 4 the highest value of 1 hour and 14 min. Only few historical records are available for the 1755 Great Lisbon Earthquake and their uncertainty is relatively high. Nevertheless, a comparison between these records and the estimated wave heights and travel times at specific locations (Sagres in Portugal, Cadiz in Spain and Safi in Morocco), and for each scenario, is presented in Table 3. The scenario that better approximates the historical maximum observed wave height of more than 10 m in Sagres is scenario 3 (medium resolution) with approx. 7 m. For the wave travel time the results show that scenarios 3, 4, 9, 13 and 18 in the coarse resolution run and scenarios 2 to 4, 8 to 10, 13, 14 and 18 in the medium resolution run fall within the proposed range of 9 to 23 min. Scenario 9 gives the best estimate for the wave travel time in the medium resolution run and scenarios 5 and 12 in the coarse resolution run. No scenario is in accordance with the historical maximum observed wave height in Cadiz, of 15 m; the highest estimate of 3.14 m is given by scenario 5 in the coarse resolution run. For the wave travel time, the results indicate that only scenario 9 in the medium resolution run fall within the proposed range in the historical record, of 1 h 3 min to 1 h 33 min. Results show that all scenarios fall within the proposed range in the historical record of 6 to 54 min, except for scenario 6 in the coarse resolution run, and scenarios 9 to 11 and 20 in the medium resolution run that overestimate the wave travel time in Safi. Scenarios 2, 7, 8, 14, 16 and 21 in the medium resolution run give the best estimate for the wave travel time. In general, Sagres presents the highest estimated wave heights of the 3 selected locations and Safi the lowest. Sagres presents also the lowest estimated travel times of the 3 selected locations, while Cadiz and Safi present similar first wave arrival times.

14

MPF+GB

JRC1/12668 JRC1/12669

HF HF

6.65 4.25 4.79

n/a 7.22 7.22

00:02 to 00:04 00:24 00:10 to 00:14

n/a 00:36 00:18

4

JRC1/12670

GB

2.70

6.93

00:18 to 00:26

01:14

5 6 7 8 9

Lisbon_1755/ scenarios/5 Lisbon_1755/ scenarios/6 JRC1/12671 JRC1/12672 JRC1/12673

GCWF MF MPF+PSF GB GB GB

4.11 2.93 3.70 3.29 1.63

n/a n/a 6.07 5.56 2.95

00:08 00:02 00:26 to 00:28 00:10 to 00:12 00:12 to 00:16

n/a n/a 00:36 00:20 00:16

10

JRC1/12675

HF

2.16

3.11

00:36 to 00:44

00:48

11 12 13

JRC1/12676 JRC1/12677 JRC1/12678

MPF PBF GCWF

2.37 2.44 3.29

4.04 3.62 5.56

00:02 to 00:06 00:08 00:10 to 00:12

00:18 00:08 00:20

14

JRC1/12679

HF

3.77

5.23

00:06 to 00:10

00:34

15 16 17 18 19

JRC1/12680 Lisbon_1755/ scenarios/16 JRC1/12681 JRC1/12683 JRC1/12684

MPF HF+MPF MPF HF HF

2.86 3.50 3.16 2.91 3.66

6.89 n/a 6.38 5.16 6.63

00:08 to 00:12 00:22 00:08 to 00:12 00:10 to 00:14 00:16

00:12 n/a 00:12 00:40 01:08

20

JRC1/12685

MPF

2.56

5.24

00:02 to 00:08

00:12

21


HF+MPF

4.08

n/a

00:20

n/a

Medium

Lisbon_1755/scenarios/1

2 3

Locations of Occurrence Coarse

1

Coarse

Medium

Wave Travel Time (hh:mm)

Medium

Maximum Estimated Wave Height (m) Coarse

JRC Scenario ID

Structural Feature

Scenario No.

Table 2: Maximum estimated wave heights, travel times and locations of occurrence for each scenario in the analysis of the 1755 Great Lisbon Earthquake.

Portugal: Sagres; Tabual and Burgau Morocco: El Behara and Boumahidi Portugal: Vila do Bispo; Sagres; Carrapateira; Tabual and Burgau Portugal: Ericeira; Assenta; Santa Cruz; Consolação; Praia de Ribeira d’Ilhas and Praia da Areia Branca Morocco: Demina; Asilah and Briech Portugal: Vila do Bispo Morocco: Mohammedia; Aç Çkhirat; Al Mancouriya and Bouzhika Morocco: El Behara; Oulad Mahdi and Boumahidi Portugal: Vila do Bispo; Sagres; Tabual and Burgau Morocco: Oulad Mahdi; El Behara; Boumahidi; Larache; Demina and Souk Khemis du Sahel Portugal: Vila do Bispo; Carrapateira and Praia de Vale Figueira Portugal: Sagres and Tabual Morocco: El Behara; Oulad Mahdi and Boumahidi Portugal: Vila do Bispo; Sagres; Tabual; Burgau; Carrapateira; Praia de Vale Figueira; Lagos and Pedra da Mina Portugal: Burgau and Lagos Morocco: Dar el Maizi Portugal: Burgau and Lagos Portugal: Sagres; Tabual; Vila do Bispo and Carrapateira Morocco: El Jadida Portugal: Vila do Bispo; Sagres; Carrapateira; Tabual; Praia de Vale Figueira and Burgau Morocco: Azemmour

n/a Morocco: Barrha Portugal: Tabual Spain: Orzola n/a n/a Morocco: El Behara Morocco: Barrha Portugal: Sagres Morocco: Barrha Portugal: Burgau Portugal: Sagres Morocco: Barrha Morocco: Mohammedia Portugal: Tabual n/a Portugal: Tabual Morocco: Douar el Arabet Spain: Tejina and Bajamar Portugal: Tabual n/a

n/a – not available Structural Features: GB – Gorringe Bank; GCWF – Gulf of Cadiz Wedge Fault; HF – Horseshoe Abyssal Plain Thrust Fault; MPF – Marquês de Pombal Fault; PBF – Portimão Bank Fault; PSF – Pereira de Sousa Fault Colours correspond to the Global Disaster Alert and Coordination System alert level for tsunamis (http://portal.gdacs.org/Models): red (max. wave height ≥3 m) high impact; orange (max. wave height ≥1 m and