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...

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 ...

[1] Lavas from the early episodes of the Pu`u `Ō`ō eruption (1983–1985) of Kı̄lauea Volcano on the island of Hawai^i display rapid compositional variation over short periods for some episodes, especially the well-sampled episode 30 with 2 wt% MgO variation in <4 hours. Little chemical variation is observed within the episode 30 lavas before or after this abrupt change, suggesting a sharp composi...

This work aims to model the optimal control of dike heights. The control problem leads to so-called Hamilton-Jacobi-Bellman (HJB) variational inequalities, where the dike-increase and reinforcement times act as input quantities to the control problem. The HJB equations are solved numerically with an Essentially Non-Oscillatory (ENO) method. The ENO methodology is originally intended for hyperbo...

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...

Dike height optimization is of major importance to the Netherlands since a large part of the country is below sea level and high water levels in rivers may cause floods. In this paper we propose a cost-benefit analysis to determine optimal dike heights. We improve the model proposed by Van Dantzig (1956) after a devastating flood in the Netherlands in 1953. For one important class of the dike i...

Statistical evaluation of historical dike failure mechanism The failure mechanism of flood protection dikes includes physical (geotechnical, seepage) processes leading to a dike breach. An awareness of the failure mechanism is required directly in dike stability calculations and indirectly for risk calculations. Statistics of historical data indicate among others the distribution and frequency ...

following a magnetic survey in saghande yazd region, the existance of a relatively important dike shape anomaly was detected. in the present study, this anomaly has been interpreted by the werner deconvolution method and parker standard curves. the location and depth of the uper surface of magnetic dike has been calculated by the werner method using a series of profiles perpendicular to the str...