Yogyakarta Quake

Merapi Ridge Fractured--Yogyakarta Threatened
Tuesday, 06 June, 2006 | 17:36 WIB

TEMPO Interactive, Yogyakarta: Sleman and Klaten lost Merapi's natural fortification. The Boyo Ridge and Gendol platform, which had been protecting the hot ash from spreading, collapsed Sunday night. “There is now no dam protecting us from hot ash any more,” said Subandriyo, the Section Head of Merapi at the Yogyakarta's Agency for the Assessment and Application of Volcanic Technology, yesterday.

“The most critical area is now the southern sector (Sleman) and southeast sector (Klaten),” he added.
A few days before, the biggest Merapi threat lay on the southwest sector, especially along the Sleman and Yogya-Magelang border.

Subandriyo said the Boyo Ridge—shaped like a 175-metre length alligator --lies on the Gendol River platform in Cangkringan, Sleman Regency, collapsed due to hot ash spewing at 18.03 Indonesian Western Indonesian Time for two hours on Sunday evening,

Not only the Boyo Ridge collapsed, but a 160-metre wall of Gendol River platform also was destroyed. According to Subandriyo, with the collapse of the Boyo Ridge and the wall of the Gendol platform, the speed of the hot ash will be more than 300 km/h .

Before the fortification collapsed, hot ash was directed to the Krasak and Boyong Rivers, and some of the hot ash was driven to the Gendol River. With the collapse of the dam, hot ash directly penetrated through the Gendol River, Kuning River (in Cangkringan and Pakem), Boyong River (in Pakem and Turi), and Woro River (in Klaten).

At Mount Merapi’s peak, the lava dome is increasingly developing. The dome presently reaches 4.2 million cubic meters. The amount of the lava, said Subandriyo, has developed to twice as much as the pre-27 May earthquake volume.

Syaiful Amin | Rini