In September 2014 there was a sharp increase in the seismic activity of the Bransfield Strait, Antarctica. More than 9,000 earthquakes with magnitudes up to 4.6 located SE of Livingston Island were detected over a period of 8 months. A few months after the series onset, local seismicity at the nearby (∼35 km) Deception Island volcano increased, displaying enhanced long‐period seismicity and several outbursts of volcano‐tectonic (VT) earthquakes. Before February 2015, VT earthquakes occurred mainly at 5–20 km SW of Deception Island. In mid‐February the numbers and sizes of VT earthquakes escalated, and their locations encompassed the whole volcanic edifice, suggesting a situation of generalized unrest. The activity continued in anomalously high levels at least until May 2015. Given the spatial and temporal coincidence, it is unlikely that the Livingston series and the Deception VT swarm were unrelated. We propose that the Livingston series may have produced a triggering effect on Deception Island volcano. Dynamic stresses associated to the seismic swarm may have induced overpressure in the unstable volcanic system, leading to a magmatic intrusion that may in turn have triggered the VT swarm. Alternatively, both the Livingston earthquakes and the VT swarm could be consequences of a magmatic intrusion at Deception Island. The Livingston series would be an example of precursory distal VT swarm, which seems to be a common feature preceding volcanic eruptions and magma intrusions in long‐dormant volcanoes.

Deception Island (South Shetland Islands) is one of the most active volcanoes in Antarctica, with more than 15 explosive eruptive events registered over the past two centuries. Recent eruptions (1967, 1969 and 1970) and volcanic unrest episodes in 1992, 1999 and 2014–15 demonstrate that the occurrence of future volcanic activity is a valid and pressing concern for scientists, logistic personnel and tourists that are visiting or are working on or near the island. Over the last few decades, intense research activity has been carried out on Deception Island to decipher the origin and evolution of this very complex volcano. To that end, a solid integration of related scientific disciplines, such as tectonics, petrology, geochemistry, geophysics, geomorphology, remote sensing, glaciology, is required. A proper understanding of the island's evolution in the past, and its present state, is essential for improving the efficiency in interpreting monitoring data recorded during volcanic unrest periods and, hence, for future eruption forecasting. In this chapter, we briefly present Deception Island's most relevant tectonic, geomorphological, volcanological and magmatic features, as well as the results obtained from decades of monitoring the island's seismic activity and ground deformation.

The region defined by the South Shetland Islands, Bransfield Sea, and Antarctic Peninsula has complex geodynamic activity resulting from the active subduction process of the Phoenix Plate under the Antarctic Plate. This subduction produces a rift of expansion along the Bransfield Sea basin between the South Shetland Islands and the Antarctic Peninsula. There is also a chain of submarine (Orca, Three Sisters, and Building A) and emerged (Deception and Pinguin) volcanoes. In 2020, there was intense seismic activity around the Orca volcano with earthquakes of up to 6.9 Mw. This paper presents displacement models of this seismic activity produced in the region. The geodetic time series of the GNSS stations located in the region were analyzed: UYBA at the Uruguayan Artigas Antarctic Base (King George Island) and PAL2 at the U.S. Palmer Antarctic Base (Anvers Island). These data were taken from the Nevada Geodetic Laboratory.

Since 1994, the Andalusian Institute of Geophysics of the University of Granada group has been monitoring the seismic activity of Deception Island volcano (South Shetland Islands, Antarctica) during summer surveys. In this review, we analyse long-period and volcanic-tectonic events, including tremor episodes, recorded from 2011–2012 to 2021–2022 surveys with a local network and a seismic array. The seismo-volcanic activity on Deception Island occurs very locally, mainly as a result of tectonic destabilization induced by volcanic activity along with regional stresses, as a consequence of rifting and subduction processes spanning the South Shetland Islands, Bransfield Strait and Antarctica Peninsula. During this period, two changes to the volcanic alert level due to different volcanic parameters can be highlighted. The first of them was caused by the 2014–2015 seismic swarm as a consequence of a great regional perturbation located to the north-east of Deception Island, which spread around to the entire volcano. The second one, in the 2019–2020 survey, was established as a result of a significant increase in deformation parameters as a prelude of the August 2020 massive earthquake swarm that occurred in the Bransfield Strait, near the Orca submarine volcano. Furthermore, in the previous 2018–2019 survey, a peak of seismic activity was also recorded.