Rapid finite-frequency microseismic noise source inversion at regional to global scales

Elastic frequency-domain finite-difference contrast source inversion method

In this work, we extend the finite-difference contrast source inversion (FDCSI) method to the frequency-domain elastic wave equations, where the parameters describing the subsurface structure are simultaneously reconstructed. The FD-CSI method is an iterative nonlinear inversion method, which exhibits several strengths. First, the finite-difference operator only relies on the background media a...

Iran's Role In Energy Security At Regional And Global Levels

A finite-difference contrast source inversion method

We present a contrast source inversion (CSI) algorithm using a finite-difference (FD) approach as its backbone for reconstructing the unknown material properties of inhomogeneous objects embedded in a known inhomogeneous background medium. Unlike the CSI method using the integral equation (IE) approach, the FD-CSI method can readily employ an arbitrary inhomogeneous medium as its background. Th...

Using Nitrogen Isotope Ratios to Assess Terrestrial Ecosystems at Regional and Global Scales

Advances in instrumentation, particularly continuous flow mass spectrometry, have made accurate and highly precise measurements of nitrogen (N) isotopes feasible across broad geographical scales. As N natural abundance measurements are made at more and more sites across diverse ecosystem types, it is now possible to compile resulting datasets and to compare patterns across ecosystems at regiona...

Regional Versus Global Finite-State Error Repair

We focus on the domain of a regional least-cost strategy in order to illustrate the viability of non-global repair models over finitestate architectures. Our interest is justified by the difficulty, shared by all repair proposals, to determine how far to validate. A short validation may fail to gather sufficient information, and in a long one most of the effort can be wasted. The goal is to pro...