Thermal Condition of the 27 October 2012 Mw 7.8 Haida Gwaii Subduction Earthquake at the Obliquely Convergent Queen Charlotte Margin

The 2012 Mw 7.8 Haida Gwaii earthquake confirmed very oblique subduction and slip partitioning at the southern Queen Charlotte margin. In this study, we re‐examine the thermal regime near the earthquake using new model constraints and with the recognition that hydrothermal circulation in the subducting oceanic crust can significantly affect the margin thermal regime. The observed heat flow values are extremely high just seaward of the trench but decrease rapidly landward. We explain this pattern as the consequence of very vigorous hydrothermal circulation in the subducting oceanic crust. Using a finite‐element model, we simulate the thermal effect of the circulation using a high‐conductivity proxy that represents a very high Nusselt number in an aquifer along the top of the oceanic plate. Our thermal model indicates that the temperature at the intersection of the megathrust and the strike‐slip Queen Charlotte fault (QCF) just seaward of the coast is about 350° C, approximately the limit of seismogenic behavior, and cooler than previous models that did not include hydrothermal circulation. The change of plate motion kinematics across the QCF approximately coincides with a down‐dip transition of the thermally controlled seismogenic behavior of the megathrust. Seaward of the QCF, the shallow megathrust accommodates mainly the margin‐normal component of relative plate motion, with the strike‐slip component accommodated by the QCF. This portion of the megathrust exhibits stick slip and produced the 2012 Haida Gwaii earthquake. Landward of the QCF, the megathrust fully accommodates the very oblique motion of the oceanic plate beneath the continental crust and exhibits creep

Ejecta Pattern and Velocities of a Boulder Crater on Ceres.

We model the reimpact pattern of ejected particles of a boulder crater on Ceres and correlate landing sites with the corresponding launch velocities

Geologic Mapping oftThe Ac-H-6 Quadrangle Of Ceres from Nasa’s Dawn Mission: Changes in Composition

Dawn Science Team is conducting a geologic mapping campaign for Ceres similar to that done for Vesta, including production of a Survey- and High Altitude Mapping Orbit (HAMO)-based global map, and a series of 15 Low Altitude Mapping Orbit (LAMO)-based quadrangle maps. In this abstract we discuss the geologic evolution of the Ac-H-6 Haulani Quadrangl

The unique geomorphology and structural geology of the Haulani crater of dwarf planet Ceres as revealed by geological mapping of equatorial quadrangle Ac-6 Haulani

The dwarf planet Ceres has been explored by NASA's Dawn spacecraft with the goal of characterizing its geology, mineralogy, topography, shape, and internal structure. One outcome of this exploration is the production of geologic maps, meant to unveil the geologic history of Ceres. In this paper, we present the geologic map of the Ac-6 Haulani quadrangle (Lat. 22°S-22°N, Long. 0°-72°E) based on Low Altitude Mapping Orbit (LAMO) (35 m/pixel) data supplemented with color and spectral data, as well as a digital terrain model from the High Altitude Mapping Orbit (HAMO) (135 m/pixel, vertical accuracy of about 10 m). The 34 km diameter Haulani crater is one of the youngest features on Ceres and the most prominent one in the quadrangle. Haulani was formed on a topographical transition in North-south direction and shows a complex morphology with a variety of lobate flows and tectonic features. Multiple cracks and depressions around the crater indicate the failure of subsurface material. These were likely formed by the subsidence of material due to the instability of the subsurface. The mapping of Ac-6 Haulani suggests that Ceres is built up of layers with different material properties. We propose that Ceres has a solid crust and a variable ice-rich subsurface consistent with previous and recent models of Ceres' interior

Crater-related cryovolcanism on Ceres

During the Dawn mission, observations at Ceres reveal numerous interesting post-impact modifications in and around craters. These modifications contain the deposition of extended plains material with pits, multiple lobate flows, and widely dispersed deposits that form a diffuse veneer on the preexisting surface

Geomorpholohy and Topography of the Interior of Occator Crater on Ceres

Geomorpholohy and Topography of the Interior of Occator Crater on Cere