Theta wave continuous for more than 1 second

Dear all,

We are using EEGLAB and MATLAB for frequency analysis of EEG. We would like to detect the number of brain waves in a specific frequency band that lasts more than 1 second, such as Fmθ waves, and the timing of their appearance and power values, rather than the power values of the entire interval. So far, we have been displaying the waveforms on a separate software and checking them visually, but is there any way to detect them in MATLAB or EEGLAB?