Figure 13
Early warning signals of SSE for three major crashes of 2015, 2016 and 2020. Each of the two columns indicates the result corresponding to one of the crashes. The first row presents the price trend of SSE for the 4 years (1000 days) prior to the crash and the corresponding detrended residuals. Autocorrelation at lag 1 does not show any clear trends, suggesting no EWS for any of these crashes in SSE. However, variance and average power spectrum show an increasing trend. The kendall-Ï„ histograms for 2016 crash and 2020 crash indicate that this trend is strong and robust