Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An analysis of Twitter messages in the 2011 Tohoku Earthquake   Social media such as Facebook and Twitter have proven to be a useful resource
to understand public opinion towards real world events. In this paper, we
investigate over 1.5 million Twitter messages (tweets) for the period 9th March
2011 to 31st May 2011 in order to track awareness and anxiety levels in the
Tokyo metropolitan district to the 2011 Tohoku Earthquake and subsequent
tsunami and nuclear emergencies. These three events were tracked using both
English and Japanese tweets. Preliminary results indicated: 1) close
correspondence between Twitter data and earthquake events, 2) strong
correlation between English and Japanese tweets on the same events, 3) tweets
in the native language play an important roles in early warning, 4) tweets
showed how quickly Japanese people's anxiety returned to normal levels after
the earthquake event. Several distinctions between English and Japanese tweets
on earthquake events are also discussed. The results suggest that Twitter data
can be used as a useful resource for tracking the public mood of populations
affected by natural disasters as well as an early warning system.

21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ