The porosity of the uncompacted soil decreased progressively from the surface to the deep region.
Zizhao Zhang, Guobin Tang, Jian Zhu 2019, 'Study on Compaction of Reclaimed Soil of Nonmetallic Mining Area in Northern Foothillsof Tianshan Mountains in Xinjiang, China', Advances in Materials Science and Engineeringhttp://dx.doi.org/10.1155/2019/2834019. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Its roof and floor developed several layers of uncompacted mudstone, indicative of good property and pressure sealing conditions.
Hao XU, Junfeng ZHANG, Dazhen TANG, Ming LI, Wenzhong ZHANG, Wenji LIN 2012, 'Controlling factors of underpressure reservoirs in the Sulige gas field, Ordos Basin',Petroleum Exploration and Developmenthttp://www.sciencedirect.com/science/article/pii/S1876380412600160. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
The liquefaction phenomena requires the presence of saturated and uncompacted sand, and a groundwater table near the ground surface.
Andrea Ninfo, Davide Zizioli, Caludia Meisina, Doriano Castaldini, Francesco Zucca,Lucia Luzi, Mattia De Amicis 2012, 'The survey and mapping of sand-boil landforms related to the Emilia 2012 earthquakes:preliminary results', Annals of Geophysicshttp://www.annalsofgeophysics.eu/index.php/annals/article/view/6114. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)