Global Earthquake Model (GEM)

The Global Earthquake Model (GEM) is a nonprofit foundation that builds and publishes open seismic hazard and risk models on a global scale. The idea came out of a science forum at the Organisation for Economic Co-operation and Development (OECD). The foundation set up in Pavia, Italy, in 2009, as a partnership between governments, research institutes and private players, insurers and reinsurers included. At the end of 2018 it released a global seismic hazard map and a global risk map, put together from regional models built with local teams. Its calculation tool, OpenQuake, is free software: probabilistic hazard (ground acceleration at a given return period), deterministic scenarios, losses on an exposure portfolio. The regional models and their input data are open to inspection, so a calculation can be rerun with a different assumption; commercial use of some datasets requires an agreement with the foundation. For an underwriter, GEM matters most where commercial models are thin, in Central Asia, Central America or much of the Middle East. Public pools and donor-backed risk financing programs use it too, because a government can read an open model and challenge it. A map is not an underwriting model, though. The hazard map gives a reference intensity on rock, without full site effects, and GEM's global exposure databases remain aggregate estimates of the building stock. A reinsurer quoting an earthquake treaty in Nepal or Peru finds a defensible starting point there. It then recalibrates against known losses and the actual quality of the insured buildings.