Sensors on the slopes of the two mountains -- Anak Krakatoa on the southern tip of Sumatra and Tangkuban Prahu in Java -- picked up an increase in volcanic activity and a buildup of gases, government volcanologist Syamsul Rizal said on Wednesday.

• 印尼火山学家上周三说，安放在苏门答腊岛南端的喀拉喀托火山和爪哇岛上的唐库班珀拉胡火山山坡上的传感器检测到这两座火山的活动在加剧，而且气体也在积聚。