SCIENCE OBJECTIVES: THE PRIMARY SURFACE FEATURES TRAVERSING THE ICE SHELL ON JUPITERS GALILEAN SATELLITE EUROPA ARE UBIQUITOUS DOUBLE RIDGES THAT SPAN VAST DISTANCES ACROSS THE SATELLITE. THESE RIDGES ARE TYPICALLY A FEW KM WIDE A FEW 100 METERS HIGH AND EXTEND HUNDREDS OF KM LATERALLY. THEY ARE SPLIT IN HALF BY A NARROW INNER TROUGH ZONE THAT IS POSTULATED TO BE THE SITE OF POSSIBLE CRYOERUPTIVEACTIVITY. IN SPITE OF THE UBIQUITY OF THESE FEATURES THERE IS NOT YET ANY GENERALLY ACCEPTED MECHANISM FOR THEIR FORMATION NOR ANY QUANTITATIVE MODELS OF HOW THEIR CHARACTERISTIC MORPHOLOGY FORMS OR HOW LONG THEY ARE ACTIVE ALTHOUGH MANY AUTHORS BELIEVE THAT THE RIDGES MAY OVERLIE FISSURES EXTENDING THROUGH THE ICE SHELL AND INTO THE LIQUID WATER OCEAN BELOW. IN THE PROPOSED RESEARCH THEPI AND TEAM PLAN TO FURTHER DEVELOP A CONCEPT WE PROPOSED SEVERAL YEARS AGO IN WHICH TIDAL FLEXING PERIODICALLY FLUSHES WATER IN AND OUT OF A LONG DYKE UNDERLYING EACH ACTIVE RIDGE; A THIN FILM OF WATER FREEZES OUT WITHIN A FEW KM OF THE SURFACE AND OVER TIME BUILDS UP A BLADE-SHAPED INTRUSIVE MASS OF ICE BENEATH THE RIDGE THAT FORCES THE ADJACENT ICE UPWARDS INTO THE OBSERVED RIDGE STRUCTURE. WEARGUED THAT THE WIDTH OF THE RIDGE REVEALS THE DEPTH TO WHICH THE ICE WEDGE EXTENDS THE WIDTH OF THE INNER VALLEY REFLECTS THE DEPTH TO THE TOP OF THE ICE WEDGE AND THE RIDGE VOLUME EQUALS THE VOLUME OF THE ICE WEDGE ITSELF. VALIDATION OF THIS MODEL WOULD CONSTRAIN THE RATE AT WHICH THE RIDGES GROW AND THE FLUX OF WATER THAT RISES JUST BENEATH THE SURFACE DURING THE EXTENSIONAL PORTION OF EACH TIDAL CYCLE. BECAUSE THE CENTRAL TROUGHS OF THESE RIDGES MAY OFFER THE MOST DIRECT ACCESS TO THE OCEAN WATER BELOW A FULL UNDERSTANDING OF THE MECHANICS AND GROWTH OF THESE RIDGES WOULD NOT ONLY CLARIFY THE PROCESS BY WHICH EUROPAS SURFACE HAS FORMED BUT MAY ALSO HELP TO TARGET FUTURE EXPLORATION AND SAMPLING OF THE SUBSURFACE OCEANS. IN ADDITION TO RIDGE GROWTH THE FACT THAT RIDGES DO NOT BECOMEARBITRARILY LARGE INDICATES THAT THE FORMATION PROCESS MUST SELF-TERMINATE AT SOME STAGE AND WE PLAN TO INVESTIGATE THE PROCESSES THAT MAY EVENTUALLY SHUT OFF ICE WEDGE FORMATION.METHODOLOGY: OUR PREVIOUS WORK USED A FINITE ELEMENT CODE TO MODEL THE COMPLEX RHEOLOGY OF ICE IN RESPONSE TO THE DEVELOPMENT OF A SUBSURFACE ICE WEDGE BUT WAS LIMITED TO ITS MECHANICAL DEFORMATION AND DID NOT DIRECTLY INCORPORATE HEAT TRANSPORT FROM THE INTRUDED ICE. THE THERMAL PART OF THE PROCESS HOWEVER IS CRUCIAL NOT ONLY BECAUSE IT DETERMINES THE LOCATIONS WHERE WATER MAY FLOW AND WHEREIT FREEZES BUT ALSO BECAUSE THE MECHANICAL PROPERTIES OF ICE ARE STRONGLY TEMPERATURE DEPENDENT. THE FISSURE BENEATH THE RIDGE MUST BE AT THE FREEZING POINT FOR WATER TO REACH THE SURFACE SO IT REPRESENTS A ZONE OF MAJOR HEAT LOSS TO THE SURFACE AS WELL AS A MECHANICALLY WEAK ZONE IN THE LITHOSPHERE WHICH MAY THUS LOCALIZE FURTHER DEFORMATION. WE PLAN TO INCORPORATE A MODERN FINITE ELEMENT CODE SUCH AS THE ABAQUS CODE ALREADY IN DAILY USE AT PURDUE UNIVERSITY WHICH INCLUDES BOTH MECHANICAL DEFORMATION AND HEAT TRANSPORT. IN ADDITION TO THE PI AND CO-IS WE PLAN TO INVOLVE A PHD STUDENT WHO WILL LEARN THE USE OF THE COMPUTER CODE AND WILL BE INTEGRALLY INVOLVED IN THE RESEARCH.RELEVANCE: THIS RESEARCH IS DIRECTLY RELEVANT TO ROSES C.3 SOLAR SYSTEM WORKINGS IN ALL THREE CATEGORIES OF LITHOSPHERES VOLCANISM AND EVOLUTION AND MODIFICATION OF SURFACES. WE PLAN TO ELUCIDATE HOW THE ICY LITHOSPHERIC SHELL OF EUROPA IS BUILT FROM THE GRADUAL FORMATION AND TERMINATION OF DOUBLE RIDGES AND EXAMINE THE RELATION OF RIDGE FORMATION TO CRYOVOLCANISM (AT LEAST AS FAR AS THEINTRUSION OF ICE JUST BENEATH THE SURFACE IF NOT THE ERUPTION OF VOLATILES DISSOLVED IN THE WATER FROM THE CENTRAL TROUGHS). MANY EUROPA IMAGES MAKE IT CLEAR THAT RIDGES ARE THE DOMINANT FEATURE ON ITS SURFACE. THIS TASK HAS BECOME EVEN MORE RELEVANT WITH THE RECENT SELECTION OF THE EUROPA MISSION.