Where plates move away from each other at spreading or divergent plate margins, volcanic eruptions are gentle extrusions of basaltic lava.Most of these occur underwater where magma rises from great depth below to fill the space created by seafloor spreading which occurs at a rate of about 10 centimetres a year. Bhopal: the Union Carbide gas leak December 3, 1984 has become a memorable day for the city of Bhopal in Madya Pradesh county, India.Particularly the Union Carbide company states a much lower total number of victims.) The cause of the accident has been researched after the disaster. (Note that the numbers of victims are not absolute, as they are different for every organization that describes the accident in books or on their websites.
Shortly after midnight, a poisonous gas cloud escaped from the Union Carbide India Limited (UCIL) pesticide factory.This sequence forms a volcanic chain such as that currently found in the Hawaiian Islands.Hotspot volcanism forms very large, low gradient shield volcanoes and are similar in composition and eruption style to those found at divergent plate boundaries.At subducting plate margins, one plate is pushed under a neighbouring plate as they squeeze together.In addition to the old, weathered plate being forced down and melted, wet sediment and seawater is forced down creating andesitic lava and more violent eruptions containing ash. Some volcanoes are found at great distances from plate boundaries and are referred to as intraplate, within plate or hot spot volcanoes.