Physical properties of magma. Genesis and ascending of magma. Volcanic activity and plate tectonics. Types and classification of volcanic eruptions. Lavas and pyroclastic. Shape of volcanoes. Succession of old and young volcanicity. Volcanic facies. Volcanic successions in the Arabian shield. Recent volcanicity in Kingdom of Saudi Arabia and Red Sea region. Mineralization related to volcanic activity. Volcanic activity and energy. Recording of volcanic activity. Risks of volcanic activity.