Seismicity Associated with the May 2010 Eruption of South Sarigan Seamount, Northern Mariana Islands

Abstract

On 29 May 2010, at approximately 11:48 UTC, an undersea volcano south of Sarigan in the Northern Mariana Islands (Figs. 1 and 2) erupted sending a cloud of volcanic ash and water vapor to 40,000 feet (12 km; Washington Volcanic Ash Advisory Center). Bathymetric data (Stern and Smoot, 1998; Embley et al. , 2007) indicate an undersea vent exists at approximately 16.582° N and 145.821° E or about 12 km southwest of Sarigan and about 30 km northeast of Anatahan (Fig. 3). The vent depth is estimated to be 184 m below sea level. Based on physical observations of water discoloration (Juan Camacho, personal comm., 2010) and satellite imagery, the eruption plume is attributed to this undersea seamount. Figure 1. Map showing locations of islands and seismic stations in the Northern Mariana Island (NMI) chain. The names of active volcanoes are underlined. The location of the South Sarigan seamount is marked with an X. Inset shows the location of the NMI relative to Japan, Asia, the Philippine Islands, and New Guinea. Figure 2. Map showing the location of undersea vent that was the site of the 29 May 2010 eruption relative to the islands of Anatahan and Sarigan. Triangles, locations of seismic stations SARN, ANNE, and ANA2. Figure 3. Bathymetry of South Sarigan seamount and vicinity. Note data gap over part of summit. Individual minimum sounding are noted for some peaks. Contour interval is 200 m with 60 m grid‐cell size. Multibeam bathymetry data sets compiled in the area of Sarigan include: National Oceanographic and Atmospheric Administration (NOAA) Coral Reef Ecosystem Division EM300 and Reson 8101 surveys (AHI‐07‐02, AHI‐07‐03, HI‐07‐02, HI‐07‐03); NOAA Vents Program EM300 (TN153 and TN167); SeaBeam 2100 data (MGLN02MV, Onnuri); Japan Agency for Marine‐Earth Science and Technology (JAMSTEC) Seabat data (NT0518); National Geophysical Data Center (NGDC) Seabeam data (1 line north of data gap). Figure and caption courtesy of Robert Embley, …