330 LAVA lead the flow into a diversion channel The levee was reduced to only a few metres thick, and 400 kg of dynamite were set in the hot wall of the levee Because of numerous technical difficulties, the breach was smaller than originally planned, and only 20% of the flow was diverted out of the main channel Next, people tried to construct a rubble barrier about 10 m high, 30 m wide, and 400 m long along the western margin of the flow Even though lava overtopped the first barrier, more barriers were formed and finally they succeeded in preventing lateral spreading of the flow field into developed areas Heimaey (Iceland) The 1973 eruption on the island of Heimaey is a famous example of fighting a lava flow by cooling it with water A fissure eruption began in January from a km long fissure across the island in the vicinity of the centre of the town of Vestmannaeyjar, one of Iceland’s major fishing ports Lava flow from the vent began to threaten the town and the port As the flow advanced to the north and east, the mouth of the port began to be buried by lava A second large lava flow moved north-west on the west side of the main flow and had covered many houses by the end of March By early May, some 300 buildings had been engulfed by lava flows or gutted by fire To prevent the advance of the lava and save the town and port, people sprayed seawater onto the moving lava during the eruption More than 30 km of water pipes and 43 pumps were used to deliver seawater at up to m3 s A total of 000 000 m3 of water was poured onto the lava The front of the lava flow was solidified by the cooling effect of the water and it stopped moving The eruption ended in July that year and the port was saved After the eruption, people made a great effort to remove the lava and tephra from the centre of the city See Also Engineering Geology: Natural and Anthropogenic Geohazards Igneous Processes Large Igneous Provinces Mantle Plumes and Hot Spots Plate Tectonics Pyroclastics Tectonics: Mid-Ocean Ridges Volcanoes Further Reading Bardintzeff JM and McBirney AR (2000) Volcanology, 2nd edn Sudbury, MA: Jones & Bartlett Publishers Cas RAF and Wright JV (1987) Volcanic Successions: Modern and Ancient London: Chapman & Hall Decker R and Decker B (1989) Volcanoes: Revised and Updated Edition New York: WH Freeman and Company Decker RW, Wright TL, and Stauffer PH (eds.) (1987) Volcanism in Hawaii Professional Paper 1350 US Geo logical Survey Fink JH (ed.) (1990) Lava Flows and Domes: Emplace ment Mechanisms and Hazard Implications IAVCEI Proceedings in Volcanology New York: Springer Verlag Green J and Short NM (1971) Volcanic Landforms and Surface Features A Photographic Atlas and Glossary New York: Springer Verlag Hall A (1996) Igneous Petrology, 2nd edn London: Long man Group Limited Macdonald GA, Abbot AT, and Peterson FL (1990) Volca noes in the Sea: The Geology of Hawaii, 2nd edn Honolulu: University of Hawaii Press Schminke HU (2003) Volcanism New York: Springer Verlag Sigurdsson H, Houghton B, McNutt ST, Rymer H, and Stix J (eds.) (2000) Encyclopedia of Volcanology San Diego: Academic Press Wright T, Takahashi TJ, and Griggs JD (1992) Hawaii Volcano Watch: A Pictorial History, 1779 1991 Hono lulu: University of Hawaii Press and Hawaii National History Association