Abstract— Padang City is prone to liquefaction phenomena due to earthquakes. These phenomena can cause various damages to structures, infrastructures, and even can also cause deaths. Therefore, as one of the urban populated cities, the information about liquefaction potential is needed. One of them is by providing a liquefaction potential map, which is useful for mitigation and seismic disaster risks strategies. This article aims to provide a digital map of liquefaction potential in Padang City that integrates with Google Maps. The map is based on 40 coordinates in 7 subdistricts in the city with 3 colored markers that represent the levels of potential liquefaction i.e. no liquefaction level, moderate liquefaction level, and severe liquefaction level. The levels are classified based on the analysis of the secondary Cone Penetration Test data by using the calculation of the Factor of Safety and Liquefaction Potential Index with an earthquake assumption of 8 SR. The result shows that the map has ben able to display information about liquefaction potential, where 32.05% coordinates are classified as no liquefaction level with the highest percentage are in Kuranji, 22.5% are classified as moderate liquefaction level with the highest percentage are in Padang Utara, and 45.0% are classified as severe liquefaction level with the highest percentage are in Koto Tangah.

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The subgrade is very important on road construction, because its functions for support the traffic loads. The subgrade is not able to bearing capacity the traffic load , can cause damage such as cracks, settlement,and deformation on the flexible pavement or rigid pavement. to solve in this problems, it is necessary to improve the mechanical properties of subgrade for increasing soil bearing capacity and reducing the swelling potential. The Sicincin ring road - Lubuk Alung, Padang Pariaman district which has deformed, settlement and cracks on the road pavement, caused by poor bearing capacity of the subgrade. To solve these problems, it is necessary to have the soil improvements (stabilization) for subgrade In this paper soil stabilization is done by mixing soil with lime and rice husk ash (variations in lime content of 5%, 8%, 11%, 14% and 17%) and rice husk ash (constant 2.5%) .The compaction test and CBR test is carried for each variation. The results in this study obtained the most optimal percentage of lime + rice husk ash is 11%, CBR design is 25%, and swelling value of 0.13%. CBR value of subgrade without lime and rice husk ash obtained CBR = 2.3%. So that there is a significantly increase in CBR value if using lime and rice husk ash as stabilization material for subgrade. These results can be used by experts to choose effective stabilization methods.