Figure 1

Most of the analysed cities show a stationary circannual crime cycle. We estimated the criminal periodicity using the global wavelet spectrum (A) from the wavelet transform of the city-level time series (each solid curve), then compared against the null model \(P_{k}\) generated from autocorrelated random noise (dashed line); only Santa Monica and Seattle failed to have the significant 1-year period (lighter colour). With the scale-averaged wavelet power (shown in (B) for selected cities), we found that these cycles are statistically stationary throughout the time series, except for Portland. Normalised time refers to the proportional amount of time to the whole time series. The temporal regularity can be seen in the reconstructed waves of crime (C) using only the circannual band (black curves)