Assessment of Sidoarjo mud flow embankment stability using very low frequency electromagnetic method

Self-Potential Method to Assess Embankment Stability: A Study related to the Sidoarjo Mud Flow

“…Figure 7 demonstrates the correlation between SP anomalies, positions sources and their uncertainty estimated by CWT analysis, and the resistivity of the subsurface at line P79-P82. At this line, the thickness of the embankment is estimated around 10 to 15 m, as identified by the first resistivity layer and supported by Rayleigh wave analysis [18,19]. The low resistivity in the first layer indicates seepage in the embankment, which is correlated to negative SP anomalies.…”

“…Furthermore, the negative SP anomalies at 0-70 m, 80-110 m, and 170-250 m were considered near-surface fractures correlated with S1, S2, and S4, respectively. Fractures at S1 and S2 were clearly mapped in the 2D DCR inversion result, while for S4 the fracture could not be identified from the 2D DCR analysis, but it was clearly revealed by inversion of the VLF-EM data [19] and by the GPR method [44]. This may be caused by the measurement point at around 170-250 m distance being limited (the observed data are based on the length of the embankment).…”

“…Figure 1 shows the measurement of the SP data lines. Observation of the SP lines was focused on the north and northeast of the LUSI embankment, because these areas have highly collapse potential [19]. The embankment in the north and northeast parts was designed with thicknesses of 11 m and 5 m for the width of the top part ( Figure 2) [20,21], but has been repaired each year (especially before the rainy season) to handle unstability.…”

“…The embankment in the north and northeast parts was designed with thicknesses of 11 m and 5 m for the width of the top part ( Figure 2) [20,21], but has been repaired each year (especially before the rainy season) to handle unstability. Consequently, P79 to P82 of the LUSI embankment was identified as being about 12 to 15 m thick in 2017 using integrated vertical electrical sounding and Rayleigh wave dispersion [19]. Instability of the LUSI embankment is generally caused by three factors [16,19]:…”

“…Consequently, P79 to P82 of the LUSI embankment was identified as being about 12 to 15 m thick in 2017 using integrated vertical electrical sounding and Rayleigh wave dispersion [19]. Instability of the LUSI embankment is generally caused by three factors [16,19]:…”