He presents the rather fascinating diagram below, plotting fatalities against earthquake magnitudes:
Dr. Bilham comments:
With a Richter magnitude of M=7 the Haiti earthquake is classed as a major earthquake, however, no previous M=7 earthquake has resulted in this many fatalities (the Messina, Italy, earthquake of 1908 killed 82,000). At 230,000 the death toll is close to being the most lethal earthquake since 1900, and the second most lethal earthquake ever. The large death-toll was caused by the almost complete absence of earthquake resistance in most of the structures in Port-au-Prince and the surrounding towns and villages.
A recent article (2009) discussing the seismic future of cities may be downloaded here. It forecasts a rising death toll from earthquakes, especially in the developing nations, where earthquake resistance building codes are either absent or not enforced.