Introduction: The Tharsis region of Mars is characterized by large volcanic and tectonic centers with distinct sets of graben systems. Many of the radially oriented grabens have been inferred to form in response to intrusion of magmatic dikes. This interpretation is based primarily upon early physical and numerical (boundary element) models that were developed originally to understand surface d...

Introduction: Lunar pyroclastic deposits can be subdivided into several modes of occurrence [1], suggesting different modes of emplacement. For example, some smaller pyroclastic deposits have been interpreted to have erupted during strombolian/hawaiian activity [2], while others are linked to vulcanian activity related to dike and sill emplacement below crater floors [3,4]. The largest pyroclas...

We examine the ascent of volatile-rich basaltic magma through a vertical dike that intersects a horizontal tunnel of comparable cross-sectional area to the dike and located 300m below the surface and initially lled with air at atmospheric pressure. This process is a simpli ed representation of some aspects of the possible interaction of a basaltic ssure eruption with a man-made tunnel, as part ...

In the year 2000, an anomalous sequence of off-fault seismicity was detected near Lake Pillsbury in northern California. The seismicity was interpreted by Hayes et al. (2005, 2006) to be associated with a dike injection. I completed a gravity survey over the location of the seismicity and used that data in gravity modeling, to test the hypothesis that the seismicity was directly linked to the i...

Three syenite dike sets, named the Santa Cruz dikes, are coeval with the 627 ± 13 Ma old porphyritic calc-alkalic Princesa Izabel granitoid, northeastern Brazil. Dike set 1 is up to 1.5 m wide, strike 030 e040 Az, roughly parallel to the regional foliation. Dike set 2 strikes 120 e130 Az and consists of xenolith-bearing syenites and is roughly parallel to dike set 3, which is up to 1.5 m wide a...

In analogy with hydrothermal processes on Earth’s seafloor, Martian hydrothermal systems may provide a mechanism for transporting water, chemicals, and energy to the surface. We model magmatic dike driven hydrothermal systems in which we consider changes to the surrounding permeability resulting from the emplacement of the dike (Craft, 2010) and calculate water fluxes to the surface. When compa...

Dike emplacement in volcanic rift zones is often associated with the injection of “bladelike” dikes, which propagate long distances parallel to the rift, but frequently remain trapped at depth and erupt only near the tip of the dike. Over geologic time, this style of dike injection implies that a greater percentage of extension is accommodated by magma accretion at depth than near the surface. ...

Shallow dike intrusion and widening was proposed several decades ago as a cause of surface faulting and graben formation on Earth. This hypothesis was subsequently applied to the spectacular linear and/or radial graben systems visible on Mars. However, a recent study has suggested that shallow dike intrusion on Mars results in contractional folding and uplift adjacent to dike walls rather than ...

As continental rifts evolve towards mid-ocean ridges, strain is accommodated by repeated episodes of faulting and magmatism. Discrete rifting episodes have been observed along two subaerial divergent plate boundaries, the Krafla segment of the Northern Volcanic Rift Zone in Iceland and the Manda-Hararo segment of the Red Sea Rift in Ethiopia. In both cases, the initial and largest dike intrusio...

In the Netherlands the current dike design policy is to design flood defence structures corresponding to an agreed flooding probability with an extra safety board of at least 0.5 m. For river dikes a return period of 1,250 years is used to determine the design water levels. A problem with this strategy is that it builds on assumptions with regard to the intrinsically uncertain probability distr...