  Using large-scale call detail records of anonymised mobile phone service
subscribers with demographic and location information, we investigate how a
long-distance residential move within the country affects the mobile
communication patterns between an ego who moved and a frequently called alter
who did not move. By using clustering methods in analysing the call frequency
time series, we find that such ego-alter pairs are grouped into two clusters,
those with the call frequency increasing and those with the call frequency
decreasing after the move of the ego. This indicates that such residential
moves are correlated with a change in the communication pattern soon after
moving. We find that the pre-move calling behaviour is a relevant predictor for
the post-move calling behaviour. While demographic and location information can
help in predicting whether the call frequency will rise or decay, they are not
relevant in predicting the actual call frequency volume. We also note that at
four months after the move, most of these close pairs maintain contact, even if
the call frequency is decreased.
