DETER is a rapid survey of alerts of evidence of alteration of forest cover in the Amazon, carried out by INPE. DETER was developed as an alert system to support the inspection and control of deforestation and forest degradation carried out by the Brazilian Institute for the Environment and Renewable Natural Resources (IBAMA) and other agencies related to this theme. From May 2004 to December 2017, DETER operated based on data from the MODIS sensor aboard the Terra satellite, which has a spatial resolution of 250 m. With this instrument it is only possible to detect changes in forest cover with an area greater than 25 hectares. Due to cloud cover, not all alterations are identified by DETER. The lower resolution of the sensors used by DETER during this period was compensated by the daily observation capacity, making the system an ideal tool to quickly inform the inspection agencies about new alterations caused in the forest cover. During this phase, DETER issued over 70,000 alerts of forest cover alteration, totaling approximately 88,000 km2. The archive generated until December 2017 by DETER can be accessed at: http://www.obt.inpe.br/deter/dados/ In August 2015, INPE began operating a new version of DETER, in response to the change in the standard of deforested areas in the Amazon. Currently, most deforestation polygons have a unit area smaller than 25 hectares. In this context, DETER has been identifying and mapping, in near real time, deforestation and other changes in forest cover with a minimum area close to 1 ha.