Mount Vesuvius:The Emergency

Planning Conundrum

Prof. David AlexanderUniversity of Florence

Vesuvius,Napoli and theCampi Flegrei

Flegreiancaldera

Circum-Vesuvian area

Vesuvius

Napoli

Somma

Sorrentine peninsula

Capri

Ischia

Pozzuoli

Somma-Vesuvius volcanic edifice

• remnants of a broad caldera (Somma),within which there is a strato-volcano(Vesuvius) 1277 metres high

• eruption styles vary through severalorders of magnitude from Strombolian(mildly explosive) to Plinian (highlyexplosive)

• eruptions have involved a'a lava flows,pyroclastic flows, phreatomagmaticexplosions, lahars (volcanic mudflows).

Eruptive

style

Volume of

ejecta (km3)

Eruptive column height (km)

Duration of

continuous blast (hrs)

Volcanic explosivity

index

Strombolian0.0001-

0.11-7 1-8 1-3

Vulcanian 0.1-1 7-15 1-12 3-4

Plinian 1-10 15-25 6-12 4-5

Ultraplinian 10-1000 25-50+ 12+ 5-8

Some characteristics of eruption styles

• About 33,000 years of activity,with strongly varied phases.

• Partly quiescent from 79 to 1631.

• Major Vesuvian-style eruptionin 1631, with pyroclastic flows.

• Lesser intermittentactivity 1631-1944.

• 20th-century eruptions 1901-4,1943-4, then quiescence.

AD 62 - earthquake: tectonic or volcanic?

MCS grade IX

AD 79:Plinian eruptionwith pyroclasticflows due to thecollapse of the

20 km-higheruption column

AD 79pyroclasticflow victim

1631 Vesuvian eruptionand pyroclastic flow

4,000 dead in Portici

1770s

1794

1901

1944: end oflong period ofsporadic eruptionsand continuousalteration ofthe profile of thevolcanic edifice.

Castellammare diStabia (Stabiae)

Vesuvius is themost heavilymonitoredvolcano in theworld:• seismicity• heat flux• tilt and swell• groundwater• gas emissions• acoustic signs

Pertinent questions:-

• how long would the warning period beand how accurate a warning is possible?

• is the eruption scenario the right one?

• how long would a volcanicemergency last?

• therefore, what are the prospectsfor a successful evacuation?

The Circum-Vesuvian area: demography

• 17 municipalities, population 650,000

• Naples, to the west, has pop. ofjust under one million and is emptyingout eastwards and westwards

• Portici has population of 80,000in 4.5 km2 - that is 18,000/km2.

The caldera ramparts of Somma wouldprotect communities such as Pomiglianod'Arco to the north but not those tothe south and west, which are directlythreatened by volcanic blast effects.

Westerlywinds prevailin the Naples area: ashfalls wouldprobably begreatest inthe denselypopulatedareas to theeast andsoutheast.

To the south, southeast and eastup to 17,000 roofs would collapseunder the weight of volcanic ash.

The maximum riskscenario involvespyroclastic flow(nuée ardente)

0 1 2 3 4 5 km

Tyrrhenian

Sea

M t Vesuvius

Portic i

E rcolano

( and Herculaneum )

M t Som m a

Naples

Barra

Pom peii

Torre

del G reco

Torre

Annunziata

San G iuseppe

Vesuviano

M ain lava flow, pyroclastic flow

and lahar hazard areas

Densely

settled areas

Tephra

fa llout areas

What if this happened...?

Lava flow hazards extend right down tothe coast and emanate from both the

central vent and subsidiary cones.

Lava flows involve both a'a and pahoehoe(viscous rhyolitic and runny basaltic) lavas.

Existing lava flows have all beengeologically dated: the rougher,more visible ones such as thesedate from the 19th century.

Emergency planning issues:

• prevention and regulationof new development

• reduction and transferof existing development

• routeway congestion andimprovement of circulation

• warning and evacuation.

• safeguarding of cultural heritage

Under thenational plan,evacuees wouldbe sent by car,bus, train andship to 16 otherregions of Italy,which wouldhave to providetemporaryaccommodationfor them.

Vesuvio 99:dry run of evacuationof Somma Vesuviana5,000 peopleshipped to Abruzzofor Sunday lunch.

MESIMEX 2007European levelregional emergencysimulation exercise(emergency servicesonly)

National Department

of Civil Protection

Mixed operations centres

(inter-municipal)

Municipal

operations centres

Provincial

prefectures

Mountain

community

associations

Provincial authorities

'Augustus'

system

Regional authorities

Rome

Naples

e.g.

TorreAnnunziata

(pop. 50,000)

Trecase(pop. 9,500)

Salerno

Italian nationalgovernment

Campania regionalgovernment

Central control Devolution

1 Scientific-technical - planning

2 Health, social assistance - veterinary

3 Mass media and public information

4 Volontary services

5 Materials and vehicles

6 Transport - traffic and access

7 Telecommunications

Nation

al to

pro

vinc

ial leve

lsEmergency Support Functions

8 Essential services

9 Census of damage, people, things

10 Search and rescue operations

11 Local authorities

12 Hazardous materials

13 Evacuation logistics - recovery areas

14 Emergency operations centres co-ord.

Nation

al to

pro

vinc

ial leve

lsEmergency Support Functions

Circum-Vesuvian evacuation

by sea southwards

northwards along Naples-Rome corridor

SE-NW along "Golden Mile"(very congested)

eastwards

VesuVia Project:

• €30,000 per family to relocate outof the 'red' (maximum hazard) zone

• over the period 2003-55,600 families took up the offer

• "20,000 families haveexpressed interest"

• target level is 150,000 people(six times greater than at present)

• but young couples are being offeredincentives to move into the area!

The cultural heritage question

Besides thearchaeological sites

of Herculaneum,Pompeii, Stabiae

and Oplontis,there are 142

Vesuvian Villas,dating from1719-1840

Villa Campolieto, Ercolano

Villa Prota, Torre del Greco Villa Pignatelli da Montecalvo

Public buildingsat high risk:• 76 schools• 19 town halls• 9 medical centres• 7 other majorpublic buildings

Total: 111 buildings.

Urban vulnerability valuesbuildings classified 'red':

• Pompei-Scafati.............8.4%• Ottaviano..................42.8%• Boscotrecase..............50.0%

• San Giuseppe Vesuviano...57.1%

1985 Pozzuoli bradyseismic crisis:57,000 people permanently relocatedout of risk zone in six months flat.

A town for 57,000evacuees constructedin only 6 months at

Monterusciello

Some emergency preparedness lessons:

• emergency planning is limited by physical,cultural and conceptual constraints

• a major eruption of Vesuvius would instantly be a national and Europeanemergency

• the relationship between predictionand warning is absolutely critical here,especially with regard to timing

• the relationship between referencescenario and response is critical: wrongscenario equals inefficient response.

Few areas of the worldhave such complexand intractable

volcanic problems.

Thank youfor listening!

David Alexander - d.alexander@alice.it

www.terrapublishing.net