Final report Topic 1.5: Actions due to volcanic eruptions J-P. - PowerPoint PPT Presentation

Urban Habitat Constructions under Catastrophic Events FINAL CONFERENCE. Naples, 16 th - 18 th September 2010 Final report – Topic 1.5: Actions due to volcanic eruptions J-P. Muzeau & A. Talon – LaMI – Blaise Pascal Univ. – Clermont-Fd, FR J-C. Thouret – Magmas & Volcans Lab., B. Pascal Univ. – Clermont-Fd, FR T. Rossetto – Dep. Civil, Environ. & Geomatic Engin, Univ. Col. London, U.K. B. Faggiano & D. De Gregorio – Dep. Struct. Engng, ‘Federico II’ Univ., Naples, IT G. Zuccaro – PLINIVS Centre. ‘Federico II’ Univ., Naples, IT M. Indirli – ENEA, Bologna, IT

Introduction 2/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

Introduction  Today, about 1/2 billion people live at risk from volcanic hazards: Naples (Vesuvius), Tokyo (Fuji), Mexico City (Popocatepetl), Auckland (Auckland field), Arequipa (El Misti)…  As the amount of people populating the area surrounding the active volcanoes increases, the risk also increases. Naples, Vesuvius, Italy 3/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

Introduction  Objectives of the COST Action C26 : – to provide a methodology to evaluate the volcanic vulnerability of urban environments towards an eruption. – to propose simple and economical mitigation interventions. Arequipa, El Misti, Peru 4/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

Content of the presentation (Part 1.5) 1. Volcanic hazards 2. Why to study volcanic hazards? 3. Effusive eruption 4. Explosive eruption 5. Secondary events 6. Impacts of ash fall 7. Impacts of pyroclastic flows 8. Mitigation strategy 9. Vulnerability, risk and damage assessment 10. Structural aspects 11. Research activity and/or guidelines 12. Further developments 5/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

1. Volcanic hazards  Direct hazards:  Fall process – Tephra falls – Ballistic projectiles  Lava flow  Pyroclastic flow  Debris flow – Lahars  Sector collapse and flank failure – Debris avalanche 6/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

1. Volcanic hazards 7/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

1. Volcanic hazards  Indirect hazards:  Earthquakes and ground deformation  Tsunami  Secondary debris flows  Post-eruption erosion and sedimentation  Atmospheric effects  Air shocks, lightning  Post-eruption famine and disease 8/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

1. Volcanic hazards 9/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

2. Why to study volcanic hazards?  Today, about 500 million people live within a distance of 100 km from an active volcano.  Twice during the 20 th century, 2 large towns were destroyed by eruptions : St Pierre (Martinique) in 1902, Armero (Colombia) in 1985.  Major population centres lie within 10 to 20 km from several large volcanoes with a likelihood of eruption during this century. 10/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

2. Why to study volcanic hazards?  It is needed: – to minimize the risk of loss life from structure collapse or damage; – to facilitate appropriate warning and evacuation systems; – to protect food-producing areas and other areas of significant economic activity; – to improve the expected performance of structures and lifelines; – to improve the functional capability of structures and lifelines and to minimize the risk of damage to hazardous facilities. 11/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

2. Why to study volcanic hazards? World map showing the main seismic and volcanic zones 12/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

2. Why to study volcanic hazards? Flow chart Steps and tasks to be carried out 13/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

3. Effusive eruption  Lava flow – A construction invested by a lava front reaches unavoidable destruction. – Lava flow produces a lateral horizontal pressure which can cause the collapse of the buildings. – Its high temperature may also affect the material strength. 14/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

3. Effusive eruption  Lava flow – Passive protection:  Proper planning of the territory and of the emergencies management. – Active protection:  Containment and/or deviation of lava flows through barriers , able to withstand lateral thrust of flow and high temperatures (e.g. barriers of earth).  Needs to study more efficient and more easily erectable innovative barriers. 15/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

4. Explosive eruption  Air fall deposits – Cover the topography with uniform thickness. – Can be considered as a gravitational distributed load. 16/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

4. Explosive eruption  Air fall deposits – Air fall deposits are weather dependant: Density & load comparison: 10 cm of snow ↔ 10 cm volcanic ash Unit weight (kg/m 3 ) Load type Load (kPa) New snow 50-70 0.05-0.07 Settled snow 200-300 0.2-0.3 Dry uncompacted ash 500-1,300 0.5-1.3 Wet compacted ash 1 000-2 000 1.0-2.0 – The high temperatures (200-400 C) may produce important thermal degradation of the mechanical properties of the materials. 17/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

4. Explosive eruption  Air fall deposits – One of the eruptive phenomena with greater risk for existing buildings and infrastructure. – The expected impact involves a very large area linked:  to the direction and intensity of the wind,  to the type of eruption, – The are removed from the most steep slopes and accumulated in the valleys. – Affect transportation networks. 18/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

4. Explosive eruption  Pyroclastic flows – The most dangerous phenomena produced during an explosive eruption  Gas-solid dispersions with high or low concentration of particles moving along the surface under gravity action. – Characterized by high temperatures . Can be partly fluidized. – The modelling of the phenomenon is very complex. 19/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

4. Explosive eruption  Pyroclastic flows: – Can produce high damages to the built environment in areas near to the vent. – Effects can be critical because of the combination of mechanical impact and thermal stress on the vertical surfaces of buildings:  main damages: impact on openings,  a fire risk is associated with the flow passage inside the building. 20/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010

4. Explosive eruption  Pyroclastic flows: – Action can be expressed by a uniformly distributed static pressure. – Temperature ranges: 200 to 350 C . – First elements to reach the collapse: glass windows and shutters . Can be protected by more resistant panels. – The lateral resistance of a building depends on the design criteria applied in ordinary load conditions:  an earthquake-proof building presents better strength and stiffness capabilities than a not earthquake-proof one. 21/31 General Report – Topic 1.5: Actions due to volcanic eruptions Jean-Pierre Muzeau – B. Pascal Univ., France – COST C26 Final Conf., Naples, 16 th - 18 th September 2010