
The SciencesJuly 1, 1989
Volcanism at Rifts
When the earth's rigid shell is rifted, the ductile rock of the mantle wells up and partially melts. Spectacular volcanic outbursts ensue when the mantle is only slightly hotter than normal

Volcanism at Rifts
When the earth's rigid shell is rifted, the ductile rock of the mantle wells up and partially melts. Spectacular volcanic outbursts ensue when the mantle is only slightly hotter than normal