With no explanation, label each line with "location-GPE", "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
Scientists
have
estimated
that
there
have
been
at
least
13
significant
earthquakes
along
the
Cascadia
subduction
zone
in
the
past
6,000
years
.
Scientists:O
have:O
estimated:O
that:O
there:O
have:O
been:O
at:O
least:O
13:O
significant:O
earthquakes:O
along:O
the:O
Cascadia:location-GPE
subduction:O
zone:O
in:O
the:O
past:O
6,000:O
years:O
.:O