Maya Tolstoy

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To fully understand the environmental and ecological impacts of the Deepwater Horizon disaster, an accurate estimate of the total oil released is required. We used optical plume velocimetry to estimate the velocity of fluids issuing from the damaged well both before and after the collapsed riser pipe was removed. We then calculated the volumetric flow rate(More)
Spreading segments of the Mid-Atlantic Ridge show negative bull's-eye anomalies in the mantle Bouguer gravity field. Seismic refraction results from 33 degrees S indicate that these anomalies can be accounted for by variations in crustal thickness along a segment. The crust is thicker in the center and thinner at the end of the spreading segment, and these(More)
Figure 1. Locations and names of three ocean-bottom seismographs (OBS) used to locate events and NOAA-PMEL’s bottom-pressure recorder (BPR). All located earthquakes are shown as green dots. Purple star indicates location of water-column anomaly as recorded during OBS deployments. Lower right figure shows outline of 1998 flow (Embley et al., 1999) compared(More)
Two-thirds of Earth's surface is formed at mid-ocean ridges, yet sea-floor spreading events are poorly understood because they occur far beneath the ocean surface. At 9 degrees 50'N on the East Pacific Rise, ocean-bottom seismometers recently recorded the microearthquake character of a mid-ocean ridge eruption, including precursory activity. A gradual(More)
Seafloor spreading is accommodated by volcanic and tectonic processes along the global mid-ocean ridge system. As spreading rate decreases the influence of volcanism also decreases, and it is unknown whether significant volcanism occurs at all at ultraslow spreading rates (<1.5 cm yr(-1)). Here we present three-dimensional sonar maps of the Gakkel ridge,(More)
On 26 December 2004, one of the largest recorded earthquakes occurred, triggering a devastating tsunami that killed an estimated 300,000 people. The event was initially classified as Mw 9.0 based on the analysis of seismic body and surface waves (Nettles and Ekstrom, 2004; Ji, 2005; Park et al., ,2005). Classical methods of magnitude calculation are(More)
Never before has a volcanic eruption on a slowor ultraslowspreading mid-ocean ridge been both observed seismically and confirmed on the seafloor. During the first half of 1999, a long-lived volcanic-spreading event occurred on the ultraslow-spreading Gakkel Ridge in the Arctic Ocean. The seismicity associated with this event was unprecedented in duration(More)
Axial volcano, which is located near the intersection of the Juan de Fuca ridge and the Cobb-Eickelberg seamount chain beneath the northeast Pacific Ocean, is a locus of volcanic activity thought to be associated with the Cobb hotspot. The volcano rises 700 metres above the ridge, has substantial rift zones extending about 50 kilometres to the north and(More)
Hydrothermal circulation at the axis of mid-ocean ridges affects the chemistry of the lithosphere and overlying ocean, supports chemosynthetic biological communities and is responsible for significant heat transfer from the lithosphere to the ocean. It is commonly thought that flow in these systems is oriented across the ridge axis, with recharge occurring(More)
Hydroacoustic data from the eastern equatorial Pacific reveal low-magnitude seismicity concentrated at the propagating tip of the Galapagos Rise in Hess Deep. The patterns of seismicity and faulting are similar to those observed in the process zone of laboratory-scale propagating tensile cracks. Because the fracture energy required for propagation scales(More)