Geological Characteristics of Mud Volcanoes and Diapirs in the Northern Continental Margin of the South China Sea: Implications for the Mechanisms Controlling the Genesis of Fluid Leakage Structures

Table 1

Characteristics of mud volcanoes and mud diapirs in the northern South China Sea [25, 39, 43, 65–68].

	Scales	Distribution	Characteristics
Yinggehai Basin	Mud diapirs tens to hundreds of square kilometers, up to 700 km^2.	Primarily distribute in the central depression of the basin.	Mud diapir belts are arranged in a row of 5 rows of geese along the long axis of the basin.
Qiongdongnan Basin	Mud diapirs.	Predominantly concentrate in the sedimentary center of the basin depression and in the deeper, thicker deposits in the transition zone of the sags and bulges.	Mud diapirs varying in scale, structural style, and piercing layers. Mud diapirs are randomly distributed but occasionally occur in groups.
Pearl River Mouth Basin	Mud diapirs in Baiyun sag reach up to 8 km, and the largest one covers an area of 1000 km^2. Mud volcanoes in Dongsha islands have widths and heights of 0.5–2.0 km and 50–200 m.	Mud diapirs of Baiyun sag extend approximately NWW and are predominantly distributed in the southwestern part of the center of Baiyun sag.	Relatively concentrated distribution, generally consistent with the NWW fault system in the late Miocene, and the piercing layers are different.
		Many active mud volcanic belts were founded in the southwestern area of the Dongsha Islands.	Mud volcanoes have characteristics of structural extrusion and are distributed in a SWW-NEE direction.
Southwest Taiwan Basin	94 mud volcanoes ranging in height from 65 to 345 m, with a pedestal diameter of approximately 680~4100 m. Mud ridges ranging from 3.9 to 56.5 km in length and 1.6 to 8.3 km in width.	Mud volcanoes and mud diapirs are primarily distributed in the deep waters of the southern depression of the basin.	Mainly distributed in the structural fault zone, mud volcanoes are mostly distributed on mud diapirs.