Mud volcanism is widespread in Azerbaijan, with over 300 land- and offshore mud volcanoes. These volcanoes are associated with oil and gas fields, and many of them are currently active. The Shikhzahirli mud volcano is located west-northwest of Baku, in the Shamakhi-Gobustan region, and is one of the world's active mud volcanoes. From 1844 to 2025, there were approximately 25 major eruptions. The last volcano eruption occurred on January 9, 2021 in three phases. The longest was the third phase, which lasted 7 minutes. Geoelectrical measurements, consisting of the vertical electrical sounding (VES) method, were performed for the first time in the Shikhzahirli mud volcano occurrence, aiming to evaluate the near-surface mud chambers, as well as to track the feeder channel. The VES measurements indicate that within the first 50 m below ground surface, no shallow-depth accumulation chambers occurred. The eruption triggered by gas accumulation appears to branch in the near-surface region; in one location, the upward migration path is almost vertical, whereas in others it is slanted. As a result of investigations, it was found that the volcano most likely has two vents located at the hinge of an anticline. The rocks in the geological section of the study area have been found to have relatively high moisture content. The probable thickness of the volcanic breccia is estimated to be consistent with the depth of the bedrock surface, which ranges from 135 to 150 m. Proposed multidirectional faults, presumably formed because of a mud volcano eruption, were identified.

Keywords: mud volcano, eruption, vertical electrical sounding, resistivity, geoelectrical section, Shikhzahirli, fault

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