On the development and implementation of a semi-dynamic datum for Indonesia

Abstract

Since the nineteenth century, several local topocentric geodetic datums have been used for surveying and mapping in Indonesia. In 1975 the Indonesian Datum 1974, which is a national topocentric datum, was introduced and then replaced by the National Geodetic Datum 1995 which is a static geocentric datum realized using GPS observations. In recent years it has been realized that, due to on-going active tectonics in the Indonesian region, the National Geodetic Datum 1995 is inadequate for surveying and mapping in some regions of Indonesia, and also for some current and emerging applications. Initial studies suggested that a semi-dynamic geocentric datum is suitable for Indonesia. The adopted new datum uses the ITRF2008 reference frame with a reference epoch of 1 January 2012. It incorporates several major deformation blocks of Indonesia, and several micro blocks to model specific deformation events such as large earthquakes. Realization of this new semi-dynamic datum will be primarily based on existing data coming from many previous national GPS campaigns that have been conducted by the Geospatial Agency of Indonesia, and from existing GPS CORS stations across Indonesia.