1 / 16

Modelling Magma Intrusion into an Underground Opening

Modelling Magma Intrusion into an Underground Opening. Presentation to VOLCANIC ERUPTION MECHANISM MODELING WORKSHOP November 14-16, 2002 University of Hew Hampshire Durham, NH 03824, USA. Ed Gaffney and Rick Rauenzahn Los Alamos National Laboratory, Los Alamos, NM 87545, USA.

fauve
Download Presentation

Modelling Magma Intrusion into an Underground Opening

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Modelling Magma Intrusion into an Underground Opening Presentation to VOLCANIC ERUPTION MECHANISM MODELING WORKSHOP November 14-16, 2002 University of Hew Hampshire Durham, NH 03824, USA Ed Gaffney and Rick Rauenzahn Los Alamos National Laboratory, Los Alamos, NM 87545, USA

  2. Modelling Magma Intrusion into an Underground Opening • Context of Yucca Mountain(Ed) • Geologic Setting • Repository Requirements • Potential Igneous Events • Goals of Modelling • CFDLIB(Rick) • Background and Basics • Version 02.1 • Volatile exsolution • Variable viscosity • Early results(Ed) • Initial Interactions • Effusive Flow

  3. Context of Yucca Mountain Geologic Setting • Fault block in rhyolitic tuff sequence • Tertiary • Water table ~600 m,repository ~300 m • Pliocene to Pleistocene basaltic eruptions • Closest (Lathrop Wells Cone) is 75 ka • ~0.15 km3 • Alkali basalt, 2-4 wt/o water

  4. Context of Yucca Mountain Repository Requirements • Exposure of target population • Over 10,000 year span • Potential hazards • Ground water seepage • Damage to waste packages from seismic activity • Volcanic intrusion

  5. Context of Yucca Mountain Potential Igneous Events • Unlikely (10-8 per year) • Intrusive/extrusive event similar to Lathrop wells • alkali basalt • 1-4% (wt) H2O • ~0.1 km3 • Dike intersects drifts, damages waste packages • gas corrosion • heat effects on integrity • Impact, drag • May erupt to surface • fissure, conduit, or dogleg

  6. Context of Yucca Mountain Goals of Modelling • Determine environment seen by waste packages • Is there a shock from first eruption into drift? • Will magma fill drift? • Size and velocity of projectiles? • Peak environments (P, T, u, dynamic pressure) along drift • “Final” environments • Evaluate mechanisms for release • Impacts of bombs, other fragments • Heating  internal gas P rises rupture • Drag effects (carried to surface, torn by diff. drag forces, ...)

  7. CFDLIB Background • Multiphase compressible and incompressible flows • 10 years in development • Test bed for models • Applications in industry, defense • Collocated (cell-centered) variables • Fluxing velocities are time-space advanced with pressure correction • ICE/MAC • Pressure waves treated implicitly (relax SS Courant condition) • Advection/viscosity explicit • General EOS, multiphase exchange laws (user)

  8. CFDLIB Background (cont’d) • Particle-in-cell method • Allows mixed Lagrangian/Eulerian treatment • State variables (m, U, x, , …) kept on particles that move with interpolated velocity • Fluid/structure interaction (history-dependent stress laws) • Example with rod penetrator

  9. CFDLIB Background Elastic Rod Penetrator

  10. CFDLIB Background Brittle Rod Penetrator

  11. CFDLIB Background YMP special needs • Vapor/magma equilibrium • Papale (1997, 1999) • Include air (extend K/J EOS by assuming ideal air) • Variable (high) viscosity • Implicit treatment • Model of Shaw (1972) • Generalized effective drag/heat transfer • Particle size/coefficients as f(k,Tk,...) • Equations of state for gas (BKW) and liquid(Us-Up)

  12. Early ResultsMagma /Tunnel Interaction

  13. Early ResultsMagma /Tunnel Interaction

  14. Early ResultsGas Jet A 20 bar gas jet expands into an atmosphere

  15. Conclusions • Goal: model magma drift interaction • CFDLIB is multifluid, multiphase code • Mixed Lagrangian/Eulerian facilitates fluid-structure interaction • Implicit treatment of pressure waves • User supplied equation of state and exchange laws • Volatile equilibrium with silicate liquid like Papale but with different equation of state • Variable (high) viscosity • Work has just begun and team is small • magma expansion into drift • effusive flow in drift (~ lava tube) • gas jet from a circular vent

More Related