Environmental and Near-Surface Geophysics

Abstract

Mud volcanoes are widespread in the world both on land and in marine basins, in collision and transtensional settings (e.g., Kholodov 2002; Limonov 2004). Their presence is often an indicator of deep-seated hydrocarbon accumulations. At the same time, mud volcanism represents great environmental hazard that must be taken into account in the design of oil-and-gas pipelines and other constructions. The main conditions for mud volcano formation are a thick sedimentary cover (several kilometers) and plastic clayey members with an anomalously high formation of pore pressure and the presence of thermal water (Pilchin 1985; Limonov 2004). Nowadays, more than 900 terrestrial and 800 offshore mud volcanoes are known or presumed to exist (Dimitrov 2002). More than a quarter of all the known mud volcanoes are concentrated within the Caucasus (e.g., Kadirov et al. 2005) and most (more than 220) (Kholodov 2002) are located within the “Abikh triangle” (Abikh 1863) near Baku (Fig. 8.1). Mud volcanoes are always confined to longitudinal faults or to the intersection nodes of longitudinal and transverse faults (Pilchin 1985). In general, pre-existing deep faults are the main controlling factors. Many mud volcanoes exist in the Black Sea and Taman Peninsula (northwestern Caucasus) as well as mid valley in the Yori River near the Georgia-Azerbaijan border (Fig. 8.1).