Seismicity Associated With the Formation of a New Island in the Southern Red Sea

Abstract

Volcanic eruptions at mid-ocean ridges are rarely witnessed due to their inaccessibility, and are therefore poorly understood. Shallow waters in the Red Sea allow the study of ocean ridge related volcanism observed close to sea level. On the 18th December 2011, Yemeni fishermen witnessed a volcanic eruption in the Southern Red Sea that led to the formation of Sholan Island. Previous research efforts to constrain the dynamics of the intrusion and subsequent eruption relied primarily on interferometric synthetic aperture radar (InSAR) methods, data for which were relatively sparse. Our study integrates InSAR analysis with seismic data from Eritrea, Yemen, and Saudi Arabia to provide additional insights into the transport of magma in the crust that fed the eruption. Twentythree earthquakes of magnitude 2.1-3.9 were located using the Oct-tree sampling algorithm. The earthquakes propagated southeastward from near Sholan Island, mainly between December 12th and December 13th. The seismicity is interpreted as being induced by emplacement of a ∼12 km-long dike. Earthquake focal mechanisms are primarily normal faulting and suggest the seismicity was caused through a combination of dike propagation and inflation. We combine these observations with new deformation modeling to constrain the location and orientation of the dike. The best-fit dike orientation that satisfies both geodetic and seismic data is NNW-SSE, parallel to the overall strike of the Red Sea. Further, the timing of the seismicity suggests the volcanic activity began as a submarine eruption on the 13th December, which became a subaerial eruption on the 18th December when the island emerged from the beneath the sea. The new intrusion and eruption along the ridge suggests seafloor spreading is active in this region.

Earthquake Analysis Suggests Dyke Intrusion in 2019 Near Tarawera Volcano, New Zealand

“…0.3-0.6 m s −1 ). Our calculated intrusion rate of 0.3-0.6 m s −1 is very similar to those recorded for basaltic dyke intrusions in the Afar rift (Belachew et al, 2011;Barnie et al, 2015), Red Sea (Eyles et al, 2018), El Hierro (Martí et al, 2013), and Iceland (Einarsson and Brandsdóttir, 1980). However, it is significantly faster than intrusion rates calculated from a rhyolite dyke intrusion in the Main Ethiopian Rift (3 × 10 −3 m s −1 ; Temtime et al, 2020).…”

The Seismo‐Acoustics of Submarine Volcanic Eruptions

“…The Surtsey eruption was accompanied by continuous tremor that was associated with magma movement and lava extrusion (Einarsson, 1974; Pálmason, 1966) and significant earthquake activity, with earthquakes up to magnitude 4.6 (Sigtryggson & Sigurðsson, 1966). The eruptions that produced the islands of Sholan and Jadid, Arabian Sea, in 2011–2013 were also accompanied by earthquake swarms with magnitudes up to 3.9 (Eyles et al., 2018). In comparison, the 2016–2017 eruption of Bogoslof produced around 47 earthquake swarms, but the earthquakes were mostly small with none having a magnitude above 2.8 (Tepp et al., 2020).…”

Revealing 60 years of Earthquake Swarms in the Southern Red Sea, Afar and the Gulf of Aden

“…In the Afar region (Ethiopia; Figure 1A), several major earthquake sequences have occurred, such as at Serdo (1969;Abdallah et al, 1979;Kebede et al, 1969), Asal Ghoubbet (1979;Abbate et al, 1995), Dobi (Jacques et al, 1989;Jacques et al, 1996), Dabbahu (2005Wright et al, 2006;Ayele et al, 2005;Ebinger et al, 2008;Grandin et al, 2005;Hamling et al, 2010;Barnie et al, 2016), Dallol (2004;Nobile et al, 2012) and during the Nabro eruption in 2010 (Hamlyn et al, 2014;Goitom et al, 2015). In addition to these earthquake swarms in Afar, notable swarms have occurred in the southern Red Sea in the Zubair Archipelago (Jónsson and Xu, 2015;Xu et al, 2015;Eyles et al, 2018) and in the Gulf of Aden (2010Aden ( -2011Leroy et al, 2012;Shuler and Nettles, 2012;Ahmed et al, 2016;Figure 1A).…”