The first global hazard datasets that were created within the scope of GEM and publicly released show a significant improvement over previously available datasets in terms of coverage, uniformity and quality control. For example, all events in the instrumental catalogue have been individually processed with the same procedure, for a more homogeneous identification of the magnitude, location, depth and uncertainty in these parameters. GEM has also invested in development of an historical catalogue and archive, given the different picture they can help paint of the seismicity in a region.
A remarkable difference in spatial distribution of events occurs when the historical catalogue is combined with events from the instrumental catalogue. It is insights like these that can help all kinds of stakeholders to understand the hazard and risk in an area better. For scientists for example it could help direct new research.
In the Middle East:
coloured dots = Instrumental Catalogue, pink squares = Historical Catalogue