What Are X-Events?

Extreme Events are events that are rare, surprising and have high social impact, usually negative but not always.
The concept of social mood is based upon understanding how a given group or society feels about its future on all time scales. On a given time scale, the mood is deemed positive if the group is optimistic about its future, negative if it is pessimistic. The biggest challenge is to find appropriate ways to measure this sentiment. Often financial market indices perform well as such “sociometers”. But other sociometers are sometimes needed if the question at hand involves the mood of a subgroup of a larger population This is a very active research topic at the current time.
Research on X-events involves identification of the various subsystems that interact to produce the event, measuring the social mood in the geographic space where the X-event is likely to take place, and determining which measures of social mood and complexity are the most appropriate for creating the landscape that the target X-event belongs to.
The concept of complexity gaps, or mismatches, also arises in understanding the likelihood of an occurrence of an X-event. In short, we must pick a complexity measure to characterize the level of complexity of the subsystems in interaction that would lead to the event. When two or more such subsystems have widely differing complexities, then there is a complexity mismatch that creates a stress or tension. When that stress becomes unsustainable, the result is a crash, i.e., the X-event.