Assertion: volcano's activity | /r/AtLocation | swarm
Facets:
value: from 2002
type: TEMPORAL
value: often
type: TEMPORAL
Source sentences:
text: As is common with earthquakes at volcanoes around the world, seismic activity at Changbaishan often occurred in swarms, especially from 2002 to 2003, when hundreds of seismic events were sometimes recorded within a single day (figure 4, table 1).