KARAKTERISTIK HUJAN DI WILAYAH LERENG GUNUNG MERAPI (Rumus Empiris, Durasi, Agihan, dan Critical Line Kali Woro)

• Main Authors: , Pudak Juni Laksana, , Prof. Ir. Joko Sujono, M. Eng., Ph.D.
• Format: Theses and Dissertations NonPeerReviewed
• Published: [Yogyakarta] : Universitas Gadjah Mada 2014
• Subjects: ETD
• Online Access: https://repository.ugm.ac.id/128126/; http://etd.ugm.ac.id/index.php?mod=penelitian_detail&sub=PenelitianDetail&act=view&typ=html&buku_id=68457
• Institution: Universitas Gadjah Mada

Volcanic debris flow on the slopes of Mount Merapi area became a serious natural disasters because of it has great destructive force and velocity. Rainfall with a certain intensity and duration is one component trigger of volcanic debris flow. Rainfall has variability of the temporal and spatial characteristics influenced by various factors such as topography and climate. Dhian Prayuda Dharma (2012) suggests to define the characteristics of the intensity of rainfall using rainfall data with a shorter duration with statistical tests to establish the best empirical IDF formula. This research was using of 30 minutes rainfall data for short duration (<3 hours) and a spreadsheet software is find representing duration and distribution of the rainfall. The most appropriate rainfall intensity formula done by the empirical IDF formula as Sherman, Kimijima, Hasper and Manonobe. Rainfall intensity analysis use Analisis Frekuensi software (based on Microsoft Excel). Volcanic debris flow occurrence analyzed with MLIT method A to establish standard rainfall index. Sherman formula best fits the IDF characteristics of rainfall in the region of the slopes of Mount Merapi. Rainfall distribution pattern shows high intensity rainfall in the first hour and then decrease in the next hour with mean distribution for the duration of 3 hours, respectively for 12%, 28%, 25%, 16%, 12%, and 7% with an interval of 30 minutes. Based on critical line, standard rainfall index is 5 mm for warning (R1) and evacuation (R2) is 28 mm.