1. Reconstruction of the 1755 Earthquake McGill University 2011 F-X Capelle – Eric Munro – Adrien Iredale

2. Table of Content 1) Reconstruction based on geophysical data Tectonic setting Generated tsunami wave 2) Local destruction and aftershocks Post 1755 earthquakes 1 st interests in seismology 3) Impact on European culture and society Colonial ambitions restricted Cultural repercussions

3. Part 1 – Reconstruction of 1755 earthquake based on geophysical data

4. Magnitude Felt area radii  Mw 8.7 ± 0.4 Compare to 1969 earthquake tsunami wave height Energy release 40 times greater than the 1969 earthquake (Mw 7.9)  Implies a 1755 magnitude between 8.9 and 9.4

5. The Tectonic Setting

6. Summary of proposed sources Figure 1: Principle tectonic structures identified around SW Iberian continental margin

7. Duration and Complexity – Ground Motion Figure 2 – Reported Durations of the 1755 mainshock

8. Macroseismic Field Figure 3 – Macroseismic MSK intensities of the 1755 mainshock

9. Farfield long period affects Malaga: “tops of high buildings fell” Milan and Amsterdam: “oscillating chandeliers from cathedral roofs” Across Holland and Germany: “many rivers and canals were sent into pronounced oscillation” Scotland: “water levels rose and fell 0.8m for a period of 10 minutes”… “so violent to threaten destruction to some houses built on lake shores”

10. Coseismic deformation Figure 4 – Potential coseismic deformation from the 1755 earthquake

11. The Local Tsunami Figure 5 – Tsunami arrival times after the 1755 mainshock

12. The Farfield Tsunami Figure 6 – Farfield tsunami arrival time from 1755 mainshock

13. Part 2 – Local destruction and aftershocks

14. Aftershocks and Triggered Earthquakes -Many aftershocks in the hours and days to follow. -Algiers, Algeria; city and harbour severely damaged. -November 27 th, 1755 Meknes, Morocco -MSK IX-X, Mw 8.5-9.4 -March 31 st, 1761 -MSK IX, Mw 8.5 (inferred)

17. -2.4m high Tsunami in Cork, Ireland -1.9m high Tsunami in Cornwall, England -1.2m high Tsunami in Barbados 3 min 2.5 min 3 min 5 min

18. Local Damage Mw 8.7 +/- 0.4, MSK IX-X -City of 240,000, and deaths between 10,000 and 100,000. -85% of the buildings were destroyed. -Art, literature, and explorations records destroyed. -Restricted colonial ambitions.

19. The Fire - Caused by thousands of candles and unattended cooking fires - Spread fast across small streets - Lack of rescue organization - Destroyed lots of important buildings that were not affected by the earthquake

20. The Start of Seismology The Prime Minister designed a national survey concerning the earthquake. Cataloging of times, locations, and physical effects began. Construction of the first earthquake resistant buildings.

21. Part 3 – Impact on European culture and society

22. Loss of Colonial Presence - Economic effort went to re-building coastal cities, not colonies. - Loss of grounds in colonies, later defeats against Spain.

23. First Earthquake Theories Kant: First non-religious earthquake theories, including movement of gases in caves.

24. The Earthquake in European Culture Age of Enlightenment: Developing philosophy leading to the modern human rights, with the distinct separation of God from life. Voltaire’s Candide: Denying a perfect world created by God J.J. Rousseau: Support for his theory that man is naturally good, and that society corrupts him.

25. References -R.A. Hindson, C. Andrade (1999), Sedimentation and hydrodynamicprocesses associated with the tsunami generated by the 1755 Lisbon earthquake, Quaternary International, Vol. 56, pp 27-38 - A.C. Johnson (1996), Seismic moment assessment of earthquakes in stable continental regions—III. New Madrid 1811-1812, Charleston 1886 and Lisbon 1755, Geophysical Journal International, Vol. 126, pp. 314-344 - J.T. Kozak, C.D. James (1998), Historical depictions of the 1755 Lisbon Earthquake, NISEE, University of Berkeley. - N. Zitinelli, F. Chierici, R.Sartori and L.Torelli (1999), The tectonic source of the 1755 Lisbon earthquake and tsunami, Annali de geofisica, Vol. 42, pp. 49-55