second time. A confirmed surtseyan type of eruption phase started at the fissure on 7 November 2011. On 25 November 2011 the eruption was ongoing with vigorous phreatic bubbles emerging. Several separate plumes of material, aligned N-S, were visible from the air, showing that the eruption was of a fissure type. The main volcano on the island, Tanganasoga, underwent rapid inflation and increased carbon dioxide gas emissions, which were a cause for concern. On 24 November there were various reports of a sulphurous smell in the El Golfo area of the island. On 27 November the coast guard vessel Salvamar Adhara collected some pumice clasts, colloquially nicknamed 'floating lava bombs' or 'lava balloons', some of many that had been ejected by the underwater eruption and floated to the surface of the sea before sinking again. In the following days, three scientific and seismic survey vessels studied the area: Sarmiento da Gamboa (bathymetry, gravity and mapping seismic profiles), Ramon Margalef (multibeam bathymetric survey, sediment sampling and the acquisition of echograms of the water column) and Cornide de Saavedra (physical and chemical evolution of the volcano stain). The depth of the volcano beneath the surface of the water was estimated at in early December; after detailed bathymetric surveys, the highest point was placed at between below the sea surface. By late February 2012 the depth of the highest point was below sea level. On 21 December 2011 it was suggested that the eruption was subsiding, as the harmonic tremors and earthquakes are decreasing in frequency; however, in early January 2012 the earthquakes were increasing in frequency and the area of the eruption appeared to be increasing, with a wider area of sea producing the steaming pumice clasts, steam and general "jacuzzi" activity. By late February 2012 a decrease in seismicity, deformation and gas release was noted. In early March the authorities on El Hierro declared the eruption to be over; this was questioned by some vulcanologists. The webcams were taken down. In mid-April 2012 the top of the cone was measured at below the surface of the sea. Passive degassing of the underwater vent continued during 2012. Climatic impacts of the October 2011 to March 2012 El Hierro submarine volcanic eruption were reported by Yim (2013). June 2012 activity Between 2 and 4 June 2012 seismic activity on the island again picked up, with small earthquake swarms indicating deep-seated magma movement below