Cooling and Vesiculation of Alae Lava Lake, Hawaii GEOLOGICAL SURVEY PROFESSIONAL PAPER 935-B Cooling and Vesiculation of Alae Lava Lake, Hawaii By D. L. PECK SOLIDIFICATION OF ALAE LAVA LAKE, HAWAII GEOLOGICAL SURVEY PROFESSIONAL PAPER 935-B Repeated measurements of temperatures in drill holes and the altitude of the surface document the cooling of a thin ponded basalt flow UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON:l978 UNITED STATES DEPARTMENT OF THE INTERIOR CECIL D. ANDRUS, Secretary GEOLOGICAL SURVEY W.A. Radlinski, Acting Director Library of Congress Cataloging in Publication Data Peck, Dallas Lynn, 1929- Cooling and vesiculation of Alae Lava Lake, Hawaii. (Solidification of Alae Lava Lake, Hawaii) (Geological Survey Professional Paper 935-B) Bibliography: p. 49-50. Supt. of Docs. No.: 119.16:935-B 1. Basalt--Hawaii--Alae Lava Lake. I. Title. II. Series. III. Series: United States Geological Survey Professional Paper 935-B. QE462.B3P4 552'.2 77-608302 For ~ale by the Superintendent of Documents, U.S. Go\·ernment Printing Office \Vashington, D.C. 20402 Stock Number 024-001-03053-5 CONTENTS Page Page Abstract -------------------------------------------------- 1 Density of Alae lava and variation with time-Continued Introduction __ _ _ _ _ __ ___ _ __ __ ____ __ _ _ _ ___ __ __ __ __ _ _ __ __ __ __ 2 Density and vesicularity ________________________________ 19 Acknowledgments______________________________________ 3 Altitude ofthe lake surface ---------------------------- 23 Methods of study -------------------------------------- 3 Changes in altitude during solidification ____________ 24 Drilling ____ __ __ __ __ ____ __ __ _ _____ __ __ __ __ __ __ __ __ 3 Changes in horizontal distance during solidification __ 30 Temperature measurements ________________________ 5 Changes in altitude during further cooling __________ 31 Measurements of the altitude of the lake surface ____ 6 Interpretation of changes in altitude ____________________ 32 Precipitation and air temperatures__________________________ 7 Subsidence of the lake surface and calculation of the Temperatures in the lava lake------------------------------ 7 coefficient of thermal expansion __ _ _ _ _ _ __ _ __ __ _ _ _ _ 32 Definition of crust and fluid lava________________________ 7 Changes in altitude of the surface during solidification Effect of coolant water on temperatures __________________ 11 of the lake _ ___ __ __ _ _ __ __ ____ __ __ ____ __ __ __ _ _ _ _ __ 33 Temperatures in fluid lava below the crust ______________ 12 Calculation of the density of fluid lava in the lake________ 35 Thermal history of the lake ________ ____________________ 13 The pattern of cooling in three dimensions __________________ 37 Maximum temperatures and temperatures at the basal Thermal properties of Alae basalt __________________________ 40 contact ______________________________________________ 17 Thermal modeling ____ __ _ _ _ _____ __ __ _ _ ______ __ _ __ _ _ _ __ ___ _ 45 Density of Alae lava and variation with time of the altitude of Conclusions ________________________________________________ 48 the lake surface__________________________________________ 19 References cited____________________________________________ 49 ILLUSTRATIONS Page FIGURE 1. Map of Alae lava lake showing contours at the base and margin and the location and identification number of surveying stations and drill holes------------------------------------------------------------------------ 4 2. Photograph showing drilling in Alae lava lake __ __ _ _________ __ __ ____ __ _ _ ____ __ __ __ _ _ __ __ __ _ __ _ _ _ __ __ ____ __ __ __ 5 3-17. Graphs showing: 3. Representative temperature profiles __ ______ ____ __ _ _____ __ _ _ __ _____ ____ _____ ___ __ _ __ __ ____ __ __ _ _ _ _ _ _ __________ 9 4. Temperature and depth of the tip of a hollow mullite probe as a function of time during its insertion into fluid lava ---- 10 5. Thickness of the upper crust near the main drilling site as a function oftime ---------------------------------- 10 6. Temperature profile across the zone of crystallization at the base of the crust on December 30, 1963 ______________ 11 7. Temperatures near the bottom of drill hole 3 after drilling through the base of the crust ________________________ 12 8. Depth of isotherms in drill hole 4 before and after drilling on November 27, 1963 ------------------------------ 12 9. Temperature profile across partly molten crust and into underlying fluid lava on November 8, 1963 ______________ 13 10. Depth of isotherms and rainfall from August 1963 to August 1967---------------------------------------------- 14 11. Depth of isotherms from August 22 to September 17, 1963 ---------------------------------------------------- 15 12. Temperature profiles in the upper part of drill hole 5 showing the effects of abundant rainfall____________________ 16 13. Temperature profiles in five drill holes on January 21, 1965, and a computed profile ---------------------------- 17 14. Maximum temperatures at three sites as a function of time---------------------------------------------------- 19 15. Proportionate depth of the maximum temperature ------------------------------------------------------------ 20 16. Average core density and porosity (vesicularity) as a function of depth__________________________________________ 20 17. Maximum size of vesicles as a function of depth -------------------------------------------------------------- 21 18. Photomicrograph of vesicular basalt------------------------------____________________________________________ 22 19. Graph showing vesicularity as a function of time______________________________________________________________ 23 20. Graph showing estimated rate of vesiculation and cumulative abundance of vesicles as a function of temperature__ 23 21. Map showing rate of change in altitude of the lake surface during solidification of the lake from August 30 to September 24 to 26, 1963-------------------------------------------------------------------------------- 24 22. Map showing rate of change in altitude of the lake surface during solidification of the lake from September 24 to 26, 1963, to September 24, 1964 ---------------------------------------------------------------------------- 29 23. Graph showing cumulative changes in altitude of five stations ------------------------------------------------ 30 III IV CONTENTS Page FIGURES 24--27. Maps showing: 24. Total uplift of the lake surface ---------------------------------------------------------------------_________ 30 25. Changes in horizontal distance between stations during solidification ofthe lake-------------------------------- 30 26. Rate of subsidence of the lake surface after complete solidification in late September 1964 ---------------------- 31 27. Estimated daily average decrease in temperature in the lake from January to August 1965, as determined from measured rates of subsidence---------------------------------------------------------------------------- 33 28-30. Graphs showing: 28. Rates of uplift and subsidence of stations on the lake compared with maximum temperatures in the lake ________ 34 29. Observed and calculated rates of uplift and subsidence at the main drilling site -------------------------------- 34 30. Temperature profiles on September 25, 1963, and August 19, 1965, and a section through the lake on September 25, 1963 -------------------------------------------------------------------------------------------------- 36 31. Map showing approximate position of the outer margins of the 1,080°C isothermal surface in the lake as a function of time -------------------------------------------------------------------------------------------------- 38 32. Map showing outer margins of the 1,000°C isothermal surface (approximately the solidus) as a function of time -- 39 33. Longitudinal cross section showing the positions of the 1,0oooc isothermal surface as a function of time ---------- 40 34. Longitudinal cross section showing the positions of the 700°C isothermal surface as a function of time ____________ 41 35-39. Graphs showing: 35. Thermal conductivity at 35°C of air-saturated Alae basalt ---------------------------------------------------- 42 36. The ratio of conductivity at high temperature to conductivity at room temperature of four samples of basalt from Alae crater -------------------------------------------------------------------------------------------------- 43 37. Calculated heat capacity of Alae basalt as a function of temperature____________________________________________ 44 38. Calculated diffusivity of solidified Alae basalt as a function of depth and time ---------------------------------- 45 39. Computed and observed temperature profiles in Alae lava lake ------------------------------------------------ 46 40. Generalized radial section showing computed position of the 1,000°C isotherm after 120, 240, and 360 days ______ 48 TABLES Page TABLE 1. Record of drill holes in Alae lava lake ____ ____ _ _ _ _ __ __ __ _ _ _ _ _ _ _ _ __ __ __ _ _ _ _ _ _ __ __ __ __ _ _ _ _ _ _ __ ____ _ _ _ _ _ _ __ ____ _ _ 5 2. Rainfall at the south rim of Alae crater ---------------------------------------------------------------------- 8 3. Temperatures in Alae lava lake______________________________________________________________________________ 52 4. Depths and values of maximum temperatures and ofbasal contact temperatures in Alae lava lake ______________ 18 5. Bulk density and porosity of drill core _ _ _ __ _ __ __ __ _ _ _ _ ______ __ _ _ _ _ _ ___ ______ _