J. Eng. Technol. Sci., Vol. 52, No. 5, 2020, 707-731 707 Received August 12 th , 2019, Revised May 4 th , 2020, Accepted for publication September 19 th 2020. Copyright ©2020 Published by ITB Institute for Research and Community Services, ISSN: 2337-5779, DOI: 10.5614/j.eng.technol.sci.2020.52.5.8 Self-Potential Method to Assess Embankment Stability: A Study related to the Sidoarjo Mud Flow Sungkono 1,* , Masithoh N. Wasilah 1 , Yekti Widyaningrum 2 , Wildan M. Hidayatullah 1 , Fandi A. Fathoni 1 & Alwi Husein 3 1 Physics Department, Faculty of Sciences, Institut Teknologi Sepuluh Nopember, Jalan Arif Rahman Hakim, Surabaya 60111, Indonesia 2 Physics Department, Universitas Bangka Belitung, Jalan Kampus Peradaban, Bangka Belitung, Indonesia 3 Pusat Pengendalian Lumpur Sidoarjo, Jalan Gayung Kebonsari No. 50, Surabaya, 60235, Indonesia *E-mail: hening_1@physics.its.ac.id Highlights:  Noise-Assisted Multivariate Empirical Mode Decomposition (NA-MEMD) can be used for qualitative interpretation of self-potential (SP) data.  Continuous Wavelet Transform (CWT) analysis was applied to identify multiple anomaly sources from SP data.  NA-MEMD and CWT were applied to SP data for qualitative and quantitative interpretations, respectively.  The combination of NA-MEMD and CWT on SP data was used to identify the location of fractures and seepage in the LUSI embankment.  The interpretation of the result was supported by direct current resistivity. Abstract. The stability of an embankment is generally influenced by a number of factors, such as deformation, fractures, overtopping, seepage, etc. Fractures and seepage are commonly found in the LUSI (Sidoarjo mud flow) embankment. In this study, analysis of self-potential (SP) data was applied to identify fractures and seepage in the LUSI embankment. Noise-Assisted Multivariate Empirical Mode Decomposition (NA-MEMD) and Continuous Wavelet Transform (CWT) were applied to determine the location of seepage and fractures in the subsurface based on SP data. The results were correlated with the 2D direct current resistivity (DCR) method, which showed that both methods worked well and were compatible in detecting and localizing fracture and seepage in the LUSI embankment. Keywords: fractures; self-potential; signal processing method; seepage; DCR. 1 Introduction Failure of the LUSI (the Sidoarjo mud flow) embankment is mainly caused by seepage. Seepage flows through cracks in the embankment body. The degree of