Eos, Vol. 72, No. 36, September 8,1992 ment," said Pilkey. The beach was replen- ished about 10 years ago. The original quartz beach was replaced with a carbonate sand. The fragmented, irregular grains contributed to the hardness, and there is the possibility of intergranular cementing. "The hardness [of the beach] is responsible for some resis- tance to erosional factors," said Pilkey. This same storm hitting even 100 miles north of Miami Beach would have likely caused more coastal damage due to the composition of the beach, he added. In the wake of little coastal damage but extreme building damage, estimated at $lS-20 billion, Pilkey and Thieler both ex- pressed disappointment at not being able to learn more about a developed shore's re- sponse to a high-intensity storm.—Susan Bush ODP Drilling at the East Pacific Rise PAGES 386-387 Understanding the origin of the ocean crust by scientific drilling at the axes of mid- ocean ridges is a high priority in the Earth science community, as reflected in the Ocean Drilling Program (ODP) Long Range Plan, the Joint Oceanographic Institutions for Deep Earth Sampling (JOIDES) Lithosphere Panel's White Paper, and several reports of the Ridge Inter-Disciplinary Global Experi- ments (RIDGE) program. The ODP Long Range Plan provides for over a dozen drilling legs at and near mid-ocean ridges prior to the year 2002, including a multileg drilling program at the East Pacific Rise (EPR). ODP Leg 142 (February-March 1992) was the first of this multileg effort and was de- voted primarily to continued testing and de- velopment of the engineering systems needed for successful drilling of bare rock at mid-ocean ridges. At the same time, it was hoped that drilling would result in cores that could be used to study volcanic and hydro- thermal processes, volcanic architecture, fluid flow, and other processes occurring at the active EPR axis. Scientific drilling on bare rock near mid- ocean ridge axes has previously been impos- sible. Since Leg 54 of the Deep Sea Drilling Project, it has been clear that new hardrock guide bases and techniques would be needed to start drill holes on bare rock. Once holes have been started, it probably will be necessary to case off unstable, rub- bly, and/or fractured intervals. As demon- strated on ODP legs 106 and 109, conven- tional casing systems and techniques will not work. Finally, in order to drill to depths of several hundred meters or more, a system is needed that can successfully penetrate and core fractured basalt flows, maintain a stable hole, and provide good core recovery. Starting in 1988, the ODP has focused on these three areas of new technology, which are also needed to successfully drill holes in other types of rock that have proved difficult to core by conventional systems (for exam- ple, interbedded chert-chalk sequences). On Leg 142, we tested a new six-sided hardrock guide base (HRB) design for stabi- lizing the drillstring and spudding new holes on bare rock. We also tested the new nested Drill-in Bottom Hole Assembly (DI-BHA) technology that allows multiple casing strings to be deployed in unstable drill holes. Finally, we carried out further tests of the Diamond Coring System (DCS) platform itself. This platform, which worked success- fully on previous engineering legs (124E and 132), is a self-contained drilling platform with active secondary heave compensation. Precise heave compensation is required for the sensitive weight-on-bit control needed by the narrow kerf, relatively fragile diamond- drilling equipment deployed from the DCS platform. The new mini HRB deployed on Leg 142 uses a gimbaled and counterbalanced 8-ft diameter reentry cone. It worked very well and now can be used routinely. Another sig- nificant step forward was the very successful deployment and use of the nested DI-BHA hardware. While a few minor improvements will be made, the concept of nested drill-in casing has now been proved effective even in the very challenging drilling environment of the EPR axis. Primary emphasis in the View of the hardrock guide base (HRB) from Alvin. Photo by Dan Fornari. near-term will be to continue improving and refining drill bits and cutting structures re- quired to extend the DI-BHA to further depths. A big disappointment and surprise on Leg 142 was the poor performance of the secondary heave compensation system on the DCS platform. In three separate bit runs on Leg 142, problems with excessive resid- ual heave resulted in poor weight-on-bit con- trol and subsequent bit destruction. Thus, although a hole (864A) was adequately pre- pared and cased for deeper penetration with the DCS, no DCS cores were, in fact, recov- ered. The reasons for failure of the secondary heave compensation are still not entirely clear. Almost certainly, one or more of the following were contributory factors: a bent hydraulic feed cylinder on the DCS, possible problems with the complex software and load measurement system that partially auto- mate DCS drilling, and greater water depth of the EPR site (Site 864) compared to the Leg 132 sites, resulting in more complex dy- namic behavior of the drillstring. The bent hydraulic feed cylinder likely corrupted the string weight data generated by a load cell that is essential for adequate DSC weight-on- bit control. Exhaustive analysis and revalua- tion of the DCS compensation system will be undertaken in the coming months to identify the problems and to consider possible solu- tions. Even though the performance of the DCS platform represents a setback, it is important to recognize that the successes with other components of the DCS system, the HRB and DI-BHA, are significant steps forward. Suc- cessful ridge crest drilling is, on balance, closer now than it was before Leg 142.—M. A. Storms, D. H. Reudelhuber, G. L. Holloway, and J. Allan, Ocean Drilling Program, Texas A&M University, College Station; and R. Ba- tiza, Department of Geology and Geophysics, University of Hawaii, Honolulu Recent Advances in Neotectonics PAGE 387 Recent advances in neotectonics was the focus of some seventy delegates from six- teen countries who met at the Geological Society of London in Piccadilly from June 15-16. The meeting, convened by Nils-Axel Morner, Lewis Owen, Ian Stewart, and Clau- dio Vita-Finzi, was sponsored by the Neotec- tonics Commission of the International Union for Quaternary Research (INQUA), the Quaternary Research Association, and the Tectonic Studies Group of the Geological Society of London. The meeting was structured around four themes: neotectonics and geophysics, neo- tectonics and topography, neotectonics and climate, and neotectonics and hazards. Post- ers and oral presentations were given equal weight, and ample time for informal discus- sion was allowed. Forty of the 106 who sub- mitted abstracts (now published in a soft- back volume) displayed their posters in the This page may be freely copied.