Mapping of underground cavities by the passive seismic standing waves method: the case study of Barsukovskaya cave (Novosibirsk region, Russia)

Abstract

This article presents the results of mapping a karst cave by the passive seismic standing waves method. Barsukovskaya cave is located about 100 km southeast of the city of Novosibirsk (Russia). The total length of the cave's passages and grottoes is estimated at about 200 m, the maximum depth from the earth's surface is about 19 m. The method for studying underground cavities used is based on the effect of the generation of standing waves by microtremor in the space between the earth's surface and the cave roof. The accumulation of amplitude spectra of a large number of microtremor records makes it possible to determine the frequencies of the first few modes of these waves. Areal passive seismic survey on the earth's surface above the cave made it possible to construct a map of the lowest mode frequency distribution over the cave roof. Since no standing waves were observed at other points, this map reflects the cave structure in plan, which confirms the comparison with the cave diagram drawn up earlier by one of the speleologists. A schematic map of the depth of the cave roof was constructed using the longitudinal wave velocity V p = 3120 m/s determined by the rock samples selected near the entrance to the cave. This map at a qualitative level also agrees with the data of speleologists, which indicate that the cave, on average, gradually becomes deeper from the entrance to its dead-end branches. The shallower depths in comparison with the data of speleologists are apparently explained by a very low estimate of the velocity determined from a rock sample taken near the entrance to the cave. The reliability of the obtained cave mapping results is confirmed by the numerical simulation results using the finite-element method.

Modal Analysis of a Lava Tube Roof Complex: Tabernacle Hill, Utah, USA

“…The integrated approach applied in this study, combining ambient vibration array data and numerical eigenfrequency modeling, shows promising potential for mapping and structural characterization of underground cavities. As opposed to previous studies that mainly exploited ambient vibration measurements for subsurface imaging of karst systems (Nehme et al 2013;Fedin et al 2021), our results highlight that a similar methodology can be successfully applied for generalized characterization and structural health monitoring of underground cavity roofs in different geological contexts. While no inferences on the lava tube stability can be made from the obtained results, our approach can represent a benchmark in the perspective of replicating non-invasive field measurements after intense events (e.g., earthquakes or heavy rainfall), or periodically monitoring potential recoverable and permanent structural damage (Bessette-Kirton et al 2022).…”

A Scientific Investigation of the Shangfang Mountain Yunshui Cave in Beijing Based on LiDAR Technology

“…Ground penetrating radar (GPR) and microgravimetric measurements can be used to map underground karst features [20] or detect buried structures [21]. The passive seismic standing wave method can also be used to study underground caves, which is based on the effect of the generation of standing waves by microtremor in the space between the earth's surface and the cave roof [22]. In addition, underwater caves can be measured using handheld echosounders [23].…”

Monitoring of the hydraulic units operation of the Sayano‐Shushenskaya hydroelectric power plant using remote seismic observations

“…According to the work of refs., 29,32,33 a set of natural frequencies of the dam were isolated during dynamic vibration testing and standing wave testing, respectively. The method of standing waves is a passive method, without the use of vibration sources, 32,[34][35][36] which makes it possible to isolate the standing waves field from the data of the microseismic vibrations field recorded in an engineering structure. It is based on the coherence property in the time vibrations of standing waves and converts recorded signals of the observation network consisting of a reference point and points changing its position into «one-time» records of standing waves.…”