Previous studies have compared the source characteristics of these significant earthquakes to those of the 1906 earthquake (Kwong et al., 2018; Nocquet et al., 2017); however, many uncertainties remain regarding the estimated characteristics of the 1906 earthquake. For example, although originally the Mw of the 1906 earthquake was determined to be 8.8, recent studies have estimated it to be ∼8.4 (e.g., Okal, 1992;Yoshimoto et al., 2017). Ye et al. ( 2016) estimated a source area that was 500-600 km in length for the earthquake, while Yoshimoto et al. (2017) proposed a moderately sized source area that was ∼300 km in length. As the 1906 earthquake was an event from the distant past, many observational data were based on eyewitnesses (e.g., Kelleher, 1972) and paper-based seismic and tsunami waveforms (e.g., Kanamori & McNally, 1982;Yoshimoto et al., 2017). Estimating the 1906 earthquake process that ruptured areas for other significant earthquakes is essential to understand earthquake activity in the Colombia-Ecuador subduction zone. Such estimations should be conducted using a thoroughly verified observational data set, especially because data sets that include large noise and biases may produce contradictions and inconsistencies.Inverse analysis using observed waveforms of an earthquake-induced tsunami is a suitable method to estimate the rupture process of an earthquake. This is because the tsunami waveform strongly reflects the results of the earthquake. The inverse analysis, alongside classical methods using observed seismic waveforms, have