Information System Engineering Geology (ISEG)

Report of the project:

• Indonesia - Management of Georisks, Province Nanggroe Aceh Darussalam (MANGEONAD)
• Indonesien - Management von Georisiken, Provinz Nanggroe Aceh Darussalam (MANGEONAD)

Targeted Impact

Indonesian and German engineering geologists during the ManGeoNAD-field campaign within the urban area of Banda Aceh, December 2005 Source: BGR

As an integrative part of the German governmental activities to support the reconstruction/rehabilitation process of the earthquake/tsunami 2004 affected Indonesian province of Nanggroe/Aceh/Darussalam (NAD) the Federal Institute for Geosciences and Natural Resources (BGR) was commissioned by the Federal Ministry for Economic Cooperation and Development (BMZ) with the implementation of a project of technical cooperation “Management of Georisk, Province NAD (ManGeoNAD)” in the period of 2005-2009.

Among different geoscientific activities an engineering geological hazard assessment in combination with spot-like seismical measurements was initiated in the first project phase. The main objectives of these specific activities are:

• Backing the political decision processes of sustainable reconstruction by the provision of surface/subsurface engineering geological information focussing on the suitability of building ground of the earthquake-prone urban area of Banda Aceh for targeted spatial planning purposes based on an “Information System Engineering Geology (ISEG)” (2006-2009).
  
  
• Establishing a “Round Table Engineering Geology” (November 2006) as an information/discussion panel for all acting partners.
  
  

• Strengthening of the Indonesian project counterparts - Badan Geologi, Bandung/Dinas Pertambangan dan Energi, Banda Aceh: increasing their engineering geological competence by implementation of the ISEG at both authorities and education on it (November 2006).

General Information about ISEG:

First “Round Table Engineering Geology”, Banda Aceh, November 2006 Source: BGR

The fully digital ISEG reflects a unique and versatile information pool about the engineering geological building ground condition of the urban area of Banda Aceh. The prototype of the ISEG was developed and designed by the Section “Georisks, Information Systems” of the Federal Institute for Geosciences and Natural Resources (BGR) Hannover/Germany between January 2006 and November 2006.

ISEG sources of information:

Engineering geological map of Banda Aceh with investigation sites and engineering geological cross-section lines Source: BGR

The ISEG is based on a comprehensive engineering geological set of lithological and geotechnical information ascertained by:

• a previous project (1977-1979) of the Indonesian Geological Survey and the British National Environment Research Council (NERC); information have been kindly provided by the British Geological Survey (BGS) Keyworth/Nottingham (August 2005)

  
  
  

• ManGeoNAD project: engineering geological field campaign within the urban area of Banda Aceh of all project partners carried out in December 2005 including laboratory investigations afterwards.

ISEG components (Status March 2007):

The Exploration Database administers 577 explorations sites (boreholes, hand auger, penetration tests, shear wave velocity profiles) including 185 sites with detailed lithological information spread over the whole urban area of Banda Aceh (used software package: GeODin 5).

The Geotechnical Database comprises 436 site-related laboratory samples with more than thousand geotechnical items (e.g. particle size, consistency, void/porosity, specific gravity/density), geotechnical in-situ information of 271 sites (penetration tests) and shear wave velocity information of 13 different profiles provided by the Leibnitz-Institute for Applied Geophysics Hannover (used software package: MS Access).

Screenshot of the ISEG Exploration Database Source: BGR

Screenshot of the Geotechnical Database Source: BGR

The GIS-based Subsurface Model was established by construction of geological surfaces using 90 intersected 2,5D cross-section data. The subsurface model is divided into five geotechnical units (clay, clayey sand, silt, sand, gravel). It covers an area of 106 km² and has a maximum depth of 22 m, a minimum depth of 0.1 m and a medium depth of 4 m below the surface.

ISEG Frontend Evaluation Tool comprises:

• Database map plotting tool

• Database factor map derivation tool

• Subsurface model evaluation tool

• Multiparameter overlay mapping tool.

(used software package modelling tool/evaluation tool: ArcViewGIS 3.x Add-On (Dependencies: 3D Analyst 1.x, Spatial Analyst 1.x)

GIS-based Subsurface Model Source: BGR

Composite screenshot of the ISEG Evaluation Tool Source: BGR

ISEG products (Status March 2007):

Based on the digital information a wide range of user-oriented ISEG products can be delivered, e. g.:

• Engineering geological subcrop maps
  
• Thickness maps of geotechnical model units
  
• Geotechnical maps sample related (settlement, soil classification, bearing capacity)
  
• Qualitative liquefaction map
  
• Building ground suitability maps/classification maps
  
• Synthetic cross-section/well log derivations at any desired point of the model
  

• Well log information (interactive graphical/tabular)

• Database related reports regarding the evaluation of geotechnical items, including statistics.

Building ground suitability map of the Banda Aceh district Kuta Alam derivated through weighted overlay (settlement, liquefaction, bearing capacity: each 33%) Source: BGR

Building ground suitability map of the Banda Aceh district Kuta Alam derivated through weighted overlay (settlement, liquefaction, bearing capacity: each 33%): the map will be immediately used in the forthcoming spatial planning process under the aegis of the spatial planning authority of the Indonesian Province NAD (BAPEDA) and the German Development Agency (GTZ).

ISEG availability and user access:

The ISEG has been accessible since November 2006 at the Dinas Pertambangan dan Energi (DISTAMBEN) in Banda Aceh and will be managed by the ManGeoNAD project partners. The findings of user specific requests can be provided on demand to all Indonesian authorities and national and international GO/NGO‘s as well, which are involved in the sustainable reconstruction process of the province NAD focussing on spatial planning.

ISEG prospects:

The ISEG application development has not been finished yet. Additional evaluation tools are going to be developed in the year 2007 and installed in Banda Aceh as soon as possible. The provision of new geological information to the DISTAMBEN to improve the ISEG data sources is highly desired.

ISEG disclaimer:

The ISEG represents an engineering geological tool with a focus on spatial planning and is not suitable to substitute site specific building ground respectively engineering structural investigations.