Vesuv

*Beginning of Eruption*	*Eruption Type*	*noter*
79	explosive	Ash-fall, pomices and lahars
472	effusive-explosive	Lava flow and lahars to north-western flank
512	???	-----
26 February 685	effusive	Imposing lava flow
787	effusive-explosive	Lahars and imposing lava flow
968	???	Lava flow to sea
27 January 1037	???	Lava flow to sea
29 May 1139	explosive	Ash-fall
1500	explosive	Ash-fall
16 December 1631	effusive-explosive	Cone collapse; lava flow to sea
3 July 1660	explosive	Ash-fall to north-east flank
13 April 1694	effusive	Lava toward Torre del Greco
25 May 1698	effusive-explosive	Damage by ash-fall to south-east flank
28 July 1707	effusive-explosive	-----
20 May 1737	effusive-explosive	A lava flow invades T. del Greco; ash-fall and lahars
23 December 1760	effusive-explosive	Opening of lateral vents on southern flank (150 m asl)
19 October 1767	effusive-explosive	Two lava flows toward T.Annunziata. and S. Giorgio a Cremano
8 August 1779	explosive	Ash and bombs over Ottaviano
15 June 1794	effusive-explosive	Opening of lateral vents on south-western flank (470 m asl)
22 October 1822	effusive-explosive	Two lava flows toward T. del Greco and Boscotrecase
23 August 1834 Oplevet af H.C.Andersen	effusive-explosive	A lava flow toward Poggiomarino
6 February 1850	effusive-explosive	-----
1 May 1855	effusive	A lava flow invades Massa and S.Sebastiano
8 December 1861	effusive-explosive	Opening of lateral vents on south-western flank (290 m asl)
15 November 1868	effusive	-----
24 April 1872	effusive-explosive	A lava flow invades Massa and S.Sebastiano
4 April 1906	effusive-explosive	A lava flow toward T.Annunziata, strong explosive activity
3 June 1929	effusive-explosive	A lava flow toward Terzigno
18 March 1944	effusive-explosive	A lava flow invades Massa and S.Sebastiano

Geomagnetisk inversion af vulkaner http://www.imm.dtu.dk/~pch/Projekter/eksproj.html

Projektvejleder: Per Christian Hansen

Baggrund: Ud fra målinger af magnetfeltet over en vulkan er det muligt at beregne de interne magnetiske forhold i vulkanen. Hermed kan man overvåge vulkanens dynamiske forhold og måske forudsige fremtidige udbrud af vulkanen.

Mere konkret består geomagnetisk inversion af rekonstruktion af en 3D fordeling af magnetisering, ud fra målinger af magnetfeltet i et eller flere lag over vulkanen. Denne reknstruktion involverer store ligningssystemer, som løses med iterative metoder.

Opgaveformulering: I dette projekt skal der opbygges en 3D model som tillader rekonstruktion af magnetisering under en vilkårlig overflade. I denne forbindelse skal det undersøges hvorledes området under vulkanen diskretiseres mest hensigtsmæssigt. Det udviklede program testes dels på syntetiske data, og dels på data fra målinger fra Vesuv.

Projektet udføres i samarbejde med Universitetet i Napoli.

Forudsætninger: 02601 Numeriske algoritmer samt et videregående kursus i numerisk analyse.

Antal deltagere: 1 eller 2.

Flere links med ekstra materiale

http://boden.uni-trier.de/Lehrveranstaltungen/Skripte/Italien2002/Datei_10_Vesuv.pdf
http://vulcan.fis.uniroma3.it/vesuvio/79_eruption.html - med animationer over teorien anført nedenfor

og besvar spørgsmålene som optakt til teoridiskussionen

a) What major towns were destroyed by Mount Vesuvius's eruption?
b) What major type of event precursed the volcanic eruption?
c) The cloud of smoke that Mount Vesuvius made was compared to a type of tree. What type of tree was it?
d) It states in the first letter that Pliny the elder was traveling to Stabiae when the eruption occured. Why was he doing this?
e) What was the approximate magnitude of the earthquakes which occured during the night of the first day of the eruption?

Recent hypotheses regarding the eruption of 79 A.D.
H.P. Sheridan reconstructed a model of the Vesuvius eruption of 79 A.D., based on geological data from the study of volcanic products present on the slopes of Mount Somma-Vesuvius, and on the historical information provided by Plinius the Younger, as well as on the most up-to-date studies. (a) During the volcano's long quiescent phase, both the viscosity and the gas content of the magma increased due to the differentiation produced by slow, continuous cooling. A thick impermeable crust of solidified magma prevented contact between the magma (within the magmatic chamber at a depth of 2-5 km in the carbonate formations) and the groundwater, which was of meteoric origin and contained in the limestone. When the pressure of the gases inside the chamber became greater than the load of the rocks above, the eruption began. Meanwhile, with the conduit open, the pressure suddenty lessened, and the resulting expansion of gases in the viscous mass produced violent esplosions. Thus the "volcanic pine" (Plinian eruptive column) was formed; the violence of the explosions split and shattered the impermeable crust inside the magmatic chamber, but the groundwater (of meteoric origin) contained and circulating in the limestone could not penetrate it because of the enormous pressure of the gases still present therein.
The first phase of the eruption ended when there was no further pressure from the gases that had accumulated in the magma and that had shot ash, pumice, solid blocks and scoriae mixed with gas more than 17 km into the air. No longer held up by the pressure of the gas, this material began to fall and buried almost all of Pompei in just a few hours, while flows of finer ash and water devastated Herculaneum and other towns on the slopes of Vesuvius. b) Activity at the mouth of the crater greatly diminished now that the upper part of the magmatic chamber had been emptied. Once the eruption ceased, many inhabitants of Pompei, possibly thieves among them, returned to the city, which was by now almost totally buried. Meanwhile the groundwater circulating deep within the limestone flowed into the magmatic chamber for about 10 hours; during that time it appeared that the eruption had ceased. (c) During the final phase the eruption recommenced with violence (at 6:00 a.m., Aug. 25), when water which had filtered into the partially empty chamber came into contact with the magma there. Catastrophic piroclastic surges, i.e. explosions on the surface of overheated, high-energy steam, formed a ring-like cloud of gases and ash around the center of the esplosion. The ring spread out horizontally with the destructive speed of a hurricane, descending the slopes of Vesuvius and destroying everything in its path in just a few minutes. Those people and animals in Pompei that did not flee died from suffocation, due to the high temperature of the clouds of overheated steam mixed with piroclastic material and other toxic fumes. The eruption ceased in less than 24 hours, after having completely destroyed the city and ruined the fertile countryside, which was burned by strong acid rains where not covered in a blanket of ash.

Eksempel på information fra de daglige online oplysninger via Internet omVesuv - Der var et jordskælv 20 marts!

Flere links med ekstra materiale

http://boden.uni-trier.de/Lehrveranstaltungen/Skripte/Italien2002/Datei_10_Vesuv.pdf

Vulkantyper	Materialer fra en vulkan
Vesuv en Stratovulkan	basalt	andesit
Hvilke andre vulkantyper er der	dacit	rhyolite