Abstract Geological mapping principles have been applied across planet Earth since William Smith's initial 1815 map. During the Space Age, these principles were applied to smaller moons and planets, appropriately adjusted for remote conditions and data, and revealing ‘one plate planets’ recording Earth's missing chapters. Yet what of Venus, Earth's ‘twin’, shrouded in opaque clouds? How can these geological mapping principles be applied to address fundamental questions of planetary history? We outline how Venus's geological mapping over the last 35 years has proceeded towards a successively integrated more global picture that has revealed a surface and history unlike Earth or the smaller planetary bodies! The current 1 : 10 M global geological map documents geological units that all formed in the last c. 20% of Venus's history. The oldest, Fortunian, involved intense deformation and building of thicker crust (tessera). The Guineverian featured near-global emplacement of vast volcanic plains. The Atlian saw prominent rift zones and large shield volcanoes. The three major phases of activity provide a basis for assessing the geological, atmospheric and geodynamical processes operating earlier in Venus's history that led to the preserved record, raising a series of questions to be investigated in the coming decade by an international armada of Venus missions.

Abstract The HOTSAT multiplatform system for the analysis of infrared data from satellites provides a framework that allows the detection of volcanic hotspots and an output of their associated radiative power. This multiplatform system can operate on both Moderate Resolution Imaging Spectroradiometer and Spinning Enhanced Visible and Infrared Imager data. The new version of the system is now implemented on graphics processing units and its interface is available on the internet under restricted access conditions. Combining the estimation of time-varying discharge rates using HOTSAT with the MAGFLOW physics-based model to simulate lava flow paths resulted in the first operational system in which satellite observations drive the modelling of lava flow emplacement. This allows the timely definition of the parameters and maps essential for hazard assessment, including the propagation time of lava flows and the maximum run-out distance. The system was first used in an operational context during the paroxysmal episode at Mt Etna on 12–13 January 2011, when we produced real-time predictions of the areas likely to be inundated by lava flows while the eruption was still ongoing. This allowed key at-risk areas to be rapidly and appropriately identified.

The whole Earth geohydrologic cycle describes the occurrence and movement of water from the clouds to the core. Reservoirs that comprise the conventional hydrologic cycle define the exosphere, whereas those reservoirs that are part of the solid Earth represent the geosphere. Exosphere reservoirs thus include the atmosphere, the oceans, surface water, glaciers and polar ice, the biosphere, and groundwater. Continental crust, oceanic crust, upper mantle, transition zone, lower mantle and the core make up the geosphere. The exosphere and geosphere are linked through the active plate tectonic processes of subduction and volcanism. While the storage capacities of reservoirs in the geosphere have been reasonably well constrained by experimental and observational studies, much uncertainty exists concerning the actual amount of water held in the geosphere. Assuming that the amount of water in the upper mantle, transition zone, and lower mantle represents only 10%, 10%, and 50% of their storage capacities, respectively, the total amount of water in the Earth's mantle (1.2 × 10 21 kg) is comparable to the amount of water held in the world's oceans (1.37 × 10 21 kg). Fluxes between reservoirs in the geohydrologic cycle vary by ~7 orders of magnitude, and range from 4.25 × 10 17 kg/yr between the oceans and atmosphere, to 5 × 10 10 kg/yr between the lower mantle and transition zone. Residence times for water in the various reservoirs of the geohydrologic cycle also show wide variation, and range from 2.6 × 10 -2 yr (~10 days) for water in the atmosphere, to 6.6 × 10 9 yr for water in the transition zone.

This paper presents a review of recent progress on the theory of orographic precipitation and a discussion of the role of preexisting atmospheric disturbances, especially their strong water vapor fluxes. I also introduce the basic elements of stable moist airflow dynamics and cloud physics, and a new linear theory of orographic precipitation. The theory is tested against two types of data: a single event of Alpine precipitation and the annual climatology of the Oregon coastal ranges. Different methods are used to determine the free “cloud-delay” parameters in the theory, including a statistical analysis of data from conventional rain gauges and isotope analysis of stream samples. The surprising threshold behavior of nonlinear accretion-dominated cloud physics is displayed. Finally, I consider the impact of scale-dependent precipitation patterns on erosion and terrain evolution.