The Internet is designed to survive when some of its components become faulty. Rerouting is an important approach to bypassing faulty links. In this paper, we propose a method to characterize inter-domain rerouting as a result of the massive earthquake in Japan on March 2011. Moreover, the characterization helps correlate inter-domain rerouting events and end-to-end path-quality degradation measured in Hong Kong. We analyse the variation of AS betweenness centrality extracted from BGP data to identify the time span when most routes changed, the ASes that were most seriously affected, and the correlative and backup paths. The results show that three major providers of inbound traffic to Hong Kong were affected by unstable routing state caused by a cable fault after the earthquake. Our work provides a new method of utilizing control plane’s information to diagnose data plane’s problem.