We discuss an inverse source formulation aimed at focusing wave energy produced by ground surface sources to target subsurface poroelastic formations. The intent of the focusing is to facilitate or enhance the mobility of oil entrapped within the target formation. The underlying forwardwave propagation problem is cast in two spatial dimensions for a heterogeneous poroelastic target embedded wit…

The increase in dimethylsulfoniopropionate (DMSP) biosynthesis measured in several nitrogen-limited marine algae may partially replace other less dense organic solutes such as glycine betaine (GBT). This raises the possibility that phytoplankton could synthesize the denser organic solute DMSP in low nutrient oceanic surface waters facilitating sinking into zones of the euphotic zone richer in …

New estimates of crustal thickness, Poisson’s ratio and crustal shear wave velocity have been obtained for 39 stations in Angola, Botswana, the Democratic Republic of Congo, Malawi,Mozambique, Namibia, Rwanda, Tanzania and Zambia by modelling P-wave receiver functions using the H–κ stacking method and jointly inverting the receiver functions with Rayleigh-wave phase and group velocitie…

The magnetic field that originates in the earth’s core is transformed across the electrically conducting mantle before being observed, at the earth’s surface or above. Assuming that the conductivity depends only on radius, it has been customary to treat the mantle as a linear time-invariant filter for the core magnetic field, with properties (as a function of the frequency ω) specifie…

We analysed four newly retrieved tide gauge records of the 1998 July 17 Papua New Guinea (PNG) tsunami to study statistical and spectral properties of this tsunami. The four tide gauge records were from Lombrum (PNG), Rabaul (PNG), Malakal Island (Palau) and Yap Island (State of Yap) stations located 600–1450 km from the source. The tsunami registered a maximum trough-to-crest wave height of …

The distribution of interevent times between two successive earthquakes is generally modelled as Gamma distribution. However, significant deviations from Gamma distribution have been observed at small interevent times. These deviations can be easily modelled through the introduction of a new parameter in the interevent time distribution. The log-likelihood estimations of the model parameters pe…

In order to trace community dynamics and reticulate evolution in hybrid species complexes, long-term comparative studies of natural populations are necessary. Such studies require the development of tools for fine-scale genetic analyses. In the present study, we developed species-diagnostic SNP-based markers for hybridizing freshwater crustaceans: the multispecies Daphnia longispina complex. Sp…

We interpreted the TRIDENT satellite derived gravity field to provide detailed insights into the spatial distribution of the crustal density structures in the area of the Yellow Sea. We used 3-D forward density modelling for the interpretation that incorporated constraints from existing geological and geophysical information. A gravity stripping method is used to separate out the gravity effect…

We imaged the azimuthal anisotropy of Rayleigh wave phase velocity (10–60 s) in northeast North China Craton using the teleseismic data recorded by a dense temporary array, and then inverted for the 3-D azimuthal anisotropy of the crust and uppermost mantle (20–110 km). The results reveal that the azimuthal anisotropy varies both horizontally and vertically. Obvious stratified azimuthal ani…

Processes governing productivity at the base of the pelagic food web of the southern Indian Ocean are influenced primarily by physical–chemical conditions with implications for the structure and function of the entire pelagic food web. Here, we report observations along a great circle transect from Cape Town, South Africa, to Broome in north western Australia. Primary production was tightly …