addition, a small part of the eastern side of the lava dome collapsed, generating a pyroclastic flow in Tar River Valley. Several large explosions were registered, with the largest at approximately 11:38 pm. The height of the ash column was estimated at 12,000 m (40,000 ft) above sea level. The volcano has become one of the most closely monitored volcanoes in the world since its eruption began, with the Montserrat Volcano Observatory taking detailed measurements and reporting on its activity to the government and population of Montserrat. The observatory is operated by the British Geological Survey, under contract to the government of Montserrat. The 9 October 2008 issue of the journal Science suggested that two interconnected magma chambers lie beneath the surface of the volcano on Montserrat – one six kilometres below the surface and the other below the surface. The journal also showed a link between surface behaviour and the size of the deeper magma chamber. On 5 February 2010, a vulcanian explosion simultaneously propelled pyroclastic flows down several sides of the mountain, and on 11 February 2010, a partial collapse of the lava dome sent large ash clouds over sections of several nearby islands, including Guadeloupe and Antigua. Inhabited areas of Montserrat itself received very little ash accumulation during either event. Gallery See also List of Seconds From Disaster episodes References External links Satellite imagery of 11 February 2010 eruption Montserrat Volcano Observatory (MVO) - Current monitoring of the Soufrière Hills Volcano in Montserrat. USGS Info on Soufrière Hills Volcano 2009 activity at Soufrière Hills Volcano, from NASA Earth Observatory Smithsonian Institution's Global Volcanism Program: Soufrière Hills Landforms of Montserrat Volcanoes of Montserrat Holocene stratovolcanoes Active volcanoes Mountains and hills of British Overseas Territories Complex volcanoes 20th-century volcanic events Natural disasters in Montserrat