Engineering-geological Investigation and Risk Assessment for Disaster Management in the Purworejo Regency, Central Java, Indonesia Nandra Eko Nugroho, Sari Bahagiarti Kusumayudha, Heru Sigit Purwanto, Wisnu Aji Kristanto, Ayu Narwastu Ciptahening
Universitas Pembangunan Nasional Veteran Yogyakarta
Abstract
In the Purworejo regency, Central Java, there is a mountainous area, called Menoreh Hills. It is known as a disaster prone area, tectonically representing volcanic arcs of the central part of Java Island of the tertiary era. The stratigraphy of the area varieties from the oldest to the youngest rocks, respectively consists of volcanic rocks of the Kaligesing and Dukuh formations, limestones of the Jonggrangan Formation, marl-calkarenite intermittent of Sentolo Formation, and alluvial deposits. The Kaligesing Formation consists of andesite pyroclastic breccia, tuffaceous breccia, and lava breccia, the Dukuh Formation consists of laharic breccia, Jonggrangan Formation comprises reef limestones, Sentolo Formation comprises layered calcarenite limestone, alternating with marl, while alluvial deposits includes loose materials with various grain size. The geological structure found in the Menoreh Hills is in the form of joints and lateral slip faults with a general pattern of North West - Southeast and Northeast - Southwest. Especially the volcanic rocks in the Menoreh Hills have experienced extensive weathering, forming soil with a thickness reaches up to 5 meters. Because of the topography with quite steep slope (>20o or >36% ), the soil of quite thick (>2m), the presence of fracture structures that quite tight, triggered by high rainfall (.2000 mm/year), Menoreh Hills can be classified as landslide prone areas. In connection with this, a risk assessment needs to be carried out in the context of developing disaster management in the Purworejo Regency area.
If your conference is listed in our system, please put our logo somewhere in your website.
Simply copy-paste the HTML code below to your website (ask your web admin):