Absolute Gravity Measurements and Gravity Networks in South America

Abstract . The main task of Commission Project CP2.7 is to establish a new Absolute Gravity Network in South America with a medium distance between the stations on the order of 1,000 m, with the re-observation of the existent absolute gravity stations to assure internal consistency in precision, reference system, method of measurement, etc.This paper presents the state of the art of all the existent information regarding Absolute Gravity Measurements in South America.Some stations have already been occupied in Brazil and Uruguay. Besides, a budget was approved for the reoccupation of absolute gravity stations in Argentina. Furthermore, eleven new stations have been measured in Chile with the micro-g FG5 No 206 and the defi nition of sites for new absolute gravity determinations has been already performed.On the other side, a strong effort was carried out in several countries in order to improve the distribution of gravity information in South America.These activities are intended to organize gravity measurements in the continent and will provide the necessary information for the height system in association with the geoid determination.The greatest effort at the moment pertains to the coordination of collecting, validating, and bringing consistency to existing data sets from among the many participating groups (countries and/or organizations).