  Abrupt large events in the Alfv\'{e}nic and sub-Alfv\'{e}nic frequency bands
in tokamaks are typically correlated with increased fast ion loss. Here,
machine learning is used to speed up the laborious process of characterizing
the behaviour of magnetic perturbations from corresponding frequency
spectrograms that are typically identified by humans. Analysis allows for
comparison between different mode character (such as quiescent,
fixed-frequency, chirping, avalanching) and plasma parameters obtained from the
TRANSP code such as the ratio of the neutral beam injection (NBI) velocity and
the Alfv\'{e}n velocity ($v_{\textrm{inj.}}/v_{\textrm{A}}$), the $q$-profile,
and the ratio of the neutral beam beta and the total plasma beta
($\beta_{\textrm{beam},i}/\beta$). In agreement with previous work by
Fredrickson et al. [Nucl. Fusion 2014, 54 093007], we find correlation between
$\beta_{\textrm{beam},i}$ and mode character. In addition, previously unknown
correlations are found between moments of the spectrograms and mode character.
Character transition from quiescent to non-quiescent behaviour for magnetic
fluctuations in the 50 - 200 kHz frequency band is observed along the boundary
$v_{\varphi} \lessapprox \frac{1}{4}(v_{\textrm{inj.}} - 3v_{\textrm{A}})$
where $v_{\varphi}$ is the rotation velocity.
