TY - JOUR

T1 - Structural cause of a missed eruption in the Harrat Lunayyir basaltic field (Saudi Arabia) in 2009

AU - Koulakov, Ivan

AU - Khrepy, Sami El

AU - Al-Arifi, Nassir

AU - Kuznetsov, Pavel

AU - Kasatkina, Ekaterina

PY - 2015

Y1 - 2015

N2 - Harrat Lunayyir is one of the most volcanically active recent basaltic fields in western Saudi Arabia. A period of substantial seismic unrest, featuring more than 30,000 local events, occurred in Harrat Lunayyir in April-June 2009. Although this crisis was presumably related to ongoing magma activity, it ended without any surface volcanic activity. We create new tomographic models of P and S velocities (VP and VS) and use them to explain the causes of this unrest and the reasons the eruption failed. A large seismic anomaly of high VP/VS ratio below 7 km depth coincides with the locations of more than 50 recent cinder cones with ages of older than 100 ka, and is interpreted as a steady-state magma reservoir. We also identify another seismic anomaly at depths below 15 km, which is interpreted as a conduit for fluids and melts from deeper sources. Because the location of this conduit is slightly outside the main reservoir, some of the incoming material was dispersed. As a result, the activation of the crustal reservoir was not sufficiently strong to pierce the rigid basaltic cover and cause an actual eruption during the crisis in 2009.

AB - Harrat Lunayyir is one of the most volcanically active recent basaltic fields in western Saudi Arabia. A period of substantial seismic unrest, featuring more than 30,000 local events, occurred in Harrat Lunayyir in April-June 2009. Although this crisis was presumably related to ongoing magma activity, it ended without any surface volcanic activity. We create new tomographic models of P and S velocities (VP and VS) and use them to explain the causes of this unrest and the reasons the eruption failed. A large seismic anomaly of high VP/VS ratio below 7 km depth coincides with the locations of more than 50 recent cinder cones with ages of older than 100 ka, and is interpreted as a steady-state magma reservoir. We also identify another seismic anomaly at depths below 15 km, which is interpreted as a conduit for fluids and melts from deeper sources. Because the location of this conduit is slightly outside the main reservoir, some of the incoming material was dispersed. As a result, the activation of the crustal reservoir was not sufficiently strong to pierce the rigid basaltic cover and cause an actual eruption during the crisis in 2009.

UR - http://www.scopus.com/inward/record.url?scp=84929460802&partnerID=8YFLogxK

U2 - 10.1130/G36271.1

DO - 10.1130/G36271.1

M3 - Article

AN - SCOPUS:84929460802

VL - 43

SP - 395

EP - 398

JO - Geology

JF - Geology

SN - 0091-7613

IS - 5

ER -