Heavy rains over the past week have resulted in cold lava flows on Mount Semeru, worrying Lumajang regency administration in East Java, which is now preparing for heavy floods.
Local disaster mitigation agency head Zainul Aini said the administration had set up a number of command posts in disaster-prone areas and mobilized 50 members from the disaster mitigation coordination unit.
"The officers will be assisted by 10 members from the rapid disaster anticipation unit, in addition to 15 men from each district. They are tasked with directly monitoring risky areas," said Zainal on Monday.
The administration is focusing on seven districts regarded as being at the greatest risk, encompassing the Besuk Sat, Besuk Kabokan, Besuk Kembar and Besuk Bang river delta areas, which are located in Pasrujambe, Kedungjajang, Pronojiwo, Ngadipuro, Tempeh, Pasirian and Yosowilangun districts.
Zainul said the riverflow areas were the main paths of cold lava from Mount Semeru and that volcanic material such as sand and rocks had been pouring down the mountain since March 23.
His office has advised residents living along rivers to be alert to the risk of floods and cold lava flow.
The office has also urged hundreds of traditional sand miners in those areas to be wary.
"The Lumajang administration cannot prohibit them (from working), but only urge them to be careful in carrying out their activities," said Zainul.
Earlier reports said that a cold lava flow had destroyed a 20-meter stretch of river dikes in Pasru Jambe district and a bridge in Pandansari village.
Mount Semeru's status is classified as "alert". Images in February showed thin white sulfurous gas from medium to high pressure at a height of 25 to 75 meters above its crater, while 107 eruptions have occurred, spewing gray smoke at medium to high pressure at 300 to 600 meters above the crater. Crater growth and molten lava has not been observed since February.
In Malang, Vice Regent Rendra Kresna said flash floods on March 23 stemming from the Lesti River, a tributary of the Barantas River, engulfed the Wajak, Turen, Poncokromo and Dampit districts. A resident of Sananrejo village, Sumai, 48, was killed when he was swept away by currents after being hit by a falling tree.
The floods also damaged seven bridges, three irrigation dams, hundreds of hectares of crops and water pipes.
In Yogyakarta, the Volcanology Research and Development Agency has reinstalled reflectors at Mount Merapi -- the most active volcano in the world -- that were destroyed and buried by lava during the eruption in 2006, which killed two volunteers.
"We have reinstalled 10 reflectors at the observation posts on the southern and western slopes of the mountain," said agency head Ratdomopurbo on Monday, adding their presence had accelerated observation activities accurately and rapidly, such as monitoring magma movement and crater deformation.
He said that despite a drop in volcanic activity, the volcano could still pose a risk in the form of cold lava flows. "It still contains a million cubic meters of material at its peak that could fall down," said Ratdomopurbo.
©Jakarta Post