NEOimpactor - A Tool for Assessing Earth's Vulnerability to the NEO Impact Hazard
Bailey, N.J.¹; Swinerd, G.G.²; Lewis, H.G.²; Crowther, R.^3
1School of Engineering Sciences; ²School of Engineering, University Southampton; ³Rutherford Appleton Laboratory

In order to understand the near Earth object (NEO) hazard, a clear understanding of the consequences resulting from an asteroid impact is required. To understand the entire impact event, three processes require modelling: the atmospheric entry phase, land impact events and ocean impact events. A range of impact generated effects (IGEs) are produced by different impact scenarios. It is these IGEs that present the significant hazard to human populations world wide, and the infrastructure they occupy.
By modelling the social and economic consequences from both land an ocean impacts, a system for analysing the NEO threat has been developed, entitled "NEOimpactor". By combining existing mathematical models for the three impact processes into one complete system, NEOimpactor has the capacity to model the various effects of a terrestrial asteroid impact and, critically, predict the consequences for the global population and infrastructure.
Analysis of multiple impact simulations provides a robust method for the provision of an integrated, global vulnerability assessment of the NEO hazard. The primary graphical outputs from NEOimpactor are in the form of relative consequence maps as shown in Figure 1. These are designed to maximise understanding, enabling them to be used widely by a non-specialist audience (see Figure 2). Manipulation of the raw data establishes a series of rankings against which all the countries of the world can be compared. Using a series of multiple-impact simulations, the system has identified the five countries of the world most at risk from the average impact hazard, as well as indicating the various factors influencing vulnerability. The results from the analysis of the potential threat from a fragmented impact event has significant implications for space based deflection studies. These results can be fed directly into the international decision making processes regarding the global NEO threat.

Figure 1: An example NEOimpactor output map showing the relative human casualties from an impact across the world. This is produced by simulating the impact of an asteroid into each of the 2048 cells of a global grid. The map is produced by shading each square according the casualty figure generated by the impact in that cell.
Figure 2: The NEOimpactor result maps can be imported directly into global representation packages, such as Google Earth shown here, enabling easy dissemination of the output data. The left hand globe presents the gridded data, while the right hand image shades each country according to their vulnerability.