Resilience patterns of human mobility in response to extreme urban floods

Abstract

Large-scale disasters can disproportionally impact different population groups, causing prominent disparity and inequality, especially for those vulnerable and marginalized ones. Here, we investigate the resilience of human mobility under the disturbance of the unprecedented “720” Zhengzhou flood in China in 2021 using 1.32 billion mobile phone signaling records generated by 4.35 million people. We find that although pluvial floods can trigger mobility reductions, the overall structural dynamics of mobility networks remain relatively stable. We also find that the low levels of mobility resilience in female, adolescent, and older adult groups are mainly due to their insufficient capabilities to maintain business-as-usual travel frequency during the flood. Most importantly, we reveal three types of counter-intuitive, yet widely existing, resilience patterns of human mobility (namely, “reverse bathtub”, “ever-increasing”, and “ever-decreasing” patterns), and demonstrate a universal mechanism of disaster-avoidance response by further corroborating that those abnormal resilience patterns are not associated with people’s gender or age. In view of the common association between travel behaviors and travelers’ socio-demographic characteristics, our findings provide a caveat for scholars when disclosing disparities in human travel behaviors during flood-induced emergencies.

Beyond Resilience Triangle: Dissecting Resilience Curve Archetypes and Properties in Human Systems Facing Weather Hazards

“…Examining resilience curves associated with human mobility enables the capture of fluctuations in human activities in response to disruptive events, such as floods, wildfires, storms, pandemics, or conflicts (Coleman, Gao, DeLeon, & Mostafavi, 2022;Farahmand, Wang, Mostafavi, & Maron, 2022;X. Gao et al, 2021;Hsu, Liu, et al, 2022;Rajput & Mostafavi, 2022Tang et al, 2023). Human mobility captures the overall functionality of human systems in communities.…”

Specifying floodwater characteristics in understanding human-mobility response: a comment to Tang et al.

“…With the reality of flood-risk incidents on the increase globally, studies such as Ref. [ 1 ] are critical. More mobility research is needed to strengthen our understanding of flood responses, particularly in larger cities.…”

“…The paper by Tang et al. [ 1 ] is methodologically innovative in their focus, data use (mobile phone data) and mapping exercise. Studies such as these provide highly useful analysis and legitimate policy suggestions for human mobility in their response to the realities of an extreme urban flood.…”

“…The Zhengzhou case [ 1 ] suggests that on a generic level floodwaters do not necessarily reduce human mobility fundamentally over an urban region. Evidently, flood-reduced mobility in some areas will be much more severe than elsewhere.…”