The aim of this paper is to propose a Mars Quantum Gravity Mission (MaQuIs). The mission is targeted at improving the data on the gravitational field of Mars, enabling studies on planetary dynamics, seasonal changes, and subsurface water reservoirs. MaQuIs follows well known mission scenarios, currently deployed for Earth, and includes state-of-the-art quantum technologies to enhance the gained scientific signal.

Subtle mounds have been discovered in the source areas of martian kilometer-sized flows and on top of summit areas of domes. These features have been suggested to be related to subsurface sediment mobilization, opening questions regarding their formation mechanisms. Previous studies hypothesized that they mark the position of feeder vents through which mud was brought to the surface. Two theories have been proposed: a) ascent of more viscous mud during the late stage of eruption and b) expansion of mud within the conduit due to the instability of water under martian conditions. Here we present experiments performed inside a low-pressure chamber, designed to investigate whether the volume of mud changes when exposed to a reduced atmospheric pressure. Depending on the mud viscosity, we observe volumetric increase of up to 30% at the martian average pressure of ~6 mbar. This is because the low pressure causes instability of the water within the mud, leading to the formation of bubbles that increase the volume of the mixture. This mechanism bears resemblance to the volumetric changes associated with the degassing of terrestrial lavas or mud volcano eruptions caused by a rapid pressure drop. We conclude that the mounds associated with putative martian sedimentary volcanoes might indeed be explained by volumetric changes of the mud. We also show that mud flows on Mars and elsewhere in the Solar System could behave differently to those found on Earth, because mud dynamics are affected by the formation of bubbles in response to the low atmospheric pressure.

Rocks around the InSight lander were measured in lander orthoimages of the near field (<10 m), in panoramas of the far field (<40 m), and in a high-resolution orbital image around the lander (1 km2). The cumulative fractional area versus diameter size-frequency distributions for four areas in the near field fall on exponential model curves used for estimating hazards for landing spacecraft. The rock abundance varies in the near field from 0.6% for the sand and pebble rich area to the east within Homestead hollow, to ~3-5% for the progressively rockier areas to the south, north and west. The rock abundance of the entire near field is just over 3%, which falls between that at the Phoenix (2%) and Spirit (5%) landing sites. Rocks in the far field (<40 m) that could be identified in both the surface panorama and a high-resolution orbital image fall on the same exponential model curve as the average near field rocks. Rocks measured in a high-resolution orbital image (27.5 cm/pixel) within ~500 m of the lander that includes several rocky ejecta craters fall on 4-5% exponential model curves, similar to the northern and western near field areas. As a result, the rock abundances observed from orbit falls on the same exponential model rock abundance curves as those viewed from the surface. These rock abundance measurements around the lander are consistent with thermal imaging estimates over larger pixel areas as well as expectations from fragmentation theory of an impacted Amazonian/Hesperian lava flow.

The Danakil depression in Ethiopia, at the end of the southern Red Sea, has been the locus of volcanic crises in 2004-10, with emplacement of 15 dykes: one, non-emergent, in Lake Asale next to Black Mountain and south of the Dallol dome during fall 2004, the others in the Dabbahu-Manda Hararo rift segment between September 2005 and May 2010. We report on a hydrothermal crisis that opened a 4.5 km long fissure in the ground, at the same time the Black Mountain dyke was intruding the crust 2 km away and parallel to it. The fissure, located north and south of Yellow Lake (Gaet’ale) and trending NNW-SSE, is still active. Its morphology is remarkably diversified, but surface evidence of the structural deformation has been lost over the years. Its formation is coeval with the intrusion of the Black Mountain dyke intrusion. It is suggested that after its documented propagation, the Black Mountain dyke propagated aseismically eastward as a sill, disrupting the stress equilibrium in the long-living Yellow Lake hydrothermal environment. The stress field was brought to rupture by the increased deviatoric stress, triggering the nucleation of a tensile fracture that propagated to the surface and released the far-field stress already released at depth by the emplacement of the dyke. This study documents the delicate intermingling of magmatic, tectonic, and hydrothermal processes at the ultimate step of continental rifting prior to the earliest stage of oceanic spreading.

The NASA InSight mission to Mars successfully landed on November 26th, 2018 in Elysium Planitia. It aims to characterize the seismic activity and constrain the internal structure of Mars. We focus on the Cerberus Fossae region, a giant fracture network of ~1200 km long situated east of the InSight landing site, and where M~3 marsquakes were detected during the past two years. It is formed of five main fossae located on the southeast of the Elysium Mons volcanic rise. We perform a detailed mapping of the entire system based on high resolution satellite images and Digital Elevation Models. The refined cartography reveals a range of morphologies associated with dike activities at depth. Width and throw measurements of the fossae are linearly correlated, suggesting a possible tectonic control on the shapes of the fossae. Widths and throws decrease toward the east, indicating the long-term direction of propagation of the dike-induced graben system. They also give insights into the geometry at depth and how the possible faults and fractures are rooted in the crust. The exceptional preservation of the fossae allows us to detect up to four scales of segmentation, each formed by a similar number of 3-4 segments/subsegments. This generic distribution is comparable to continental faults and fractures on Earth. We anticipate higher stress and potential for marsquakes within intersegment zones and at graben tips.

Orbital and surface observations demonstrate that aeolian activity is occurring on Mars. Here we report the aeolian changes observed in situ by NASA's InSight lander during the first 400 sols of operations. Aeolian changes include creep of grains with diameters of up to 3 mm, dust removal, dark trails left by passing vortices and possible saltation. InSight has observed such changes by using, for the first time, simultaneous imaging and continuous, high-frequency meteorological, seismological, and magnetic measurements. We show that this multi-instrument combination constrains both the timing, and specific atmospheric conditions during which, aeolian changes occur. The observed changes are infrequent and episodic, consistently occur between noon and 3 pm, and are systematically associated with the passage of convective vortices. The sudden onset of peak vortex wind speeds promotes particle motion during sequences of enhanced vortex activity and stronger ambient winds. Aeolian changes are correlated with excursions in ground acceleration and magnetic field strength, suggesting vortex-induced ground deformation and charged-particle motion.