Final answer:
Lava flows are the volcanic hazard that destroys infrastructure but typically doesn't cause loss of life due to their slower movement, allowing for evacuation.
Step-by-step explanation:
The volcanic hazard that typically destroys infrastructure but often does not result in loss of life is lava flows. Unlike some other volcanic phenomena such as pyroclastic flows, which are fast-moving, hot, and exceedingly dangerous, or volcanic gases that can be toxic, lava flows tend to move more slowly, allowing people the time to evacuate.
The slow movement of lava gives ample warning for humans to move to safety, however, it can cause widespread damage to buildings, roads, and other structures in its path. An example of this can be seen in the eruptions of Hawaiian volcanoes, which are known for their effusive eruptions that produce lava flows rather than explosive events.