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Saturday, June 24, 2023

Kaʻū News Briefs, Friday, June 23, 2023

Farmers and Gardeners rely on soil testing and other analytical services from University of Hawai'i.
Photo from UH
SOIL TESTING BY UNIVERSITY OF HAWAI'I IN HONOLULU, A SERVICE REGULARLY USED BY MANY KAʻŪ FARMERS and backyard gardeners, will no longer be available, according to the College of Tropical Agriculture & Human Resources. UH Hilo Analytical Lab will continue accepting soil samples. See https://hilo.hawaii.edu/analab/
     The CTAHR Dean, Dr. Ania Wieczorek, sent out a statement saying, "CTAHR's Agricultural Diagnostic Service Center was conceived and dedicated to providing analytical services (testing soil, plant tissue, forage, feed, and food) and diagnostic services (plant disease, weed, insect, and nematode identification) to growers across the state. 
    "While many of these services continue to this day, we recognize that our soil testing program has not been linked adequately to ongoing research opportunities and the application of the latest science and technology of soil management. Working together with faculty and ADSC staff, we have developed a plan that calls for transitioning the ADSC soil and plant analysis lab in Sherman Laboratory to a faculty run, multi-user soil research lab. As we proceed with this transition, we wish to communicate to all our stakeholders that after June 27, 2023, we will no longer be able to accept soil, plant, forage, feed, and food samples from the public. For all samples delivered by this date, the ADSC lab will continue to process submitted samples until all have been analyzed."
CTAHR explains importance of soil testing at https://www.ctahr.hawaii.edu/site/extsl.aspx
     After June 27th, CTAHR will provide the name and location of alternative laboratories where one may send samples for analysis. "Additionally, [as time and expertise allows] CTAHR faculty will continue to assist our stakeholders in interpreting analytical results from recommended laboratories. We are excited by this opportunity to transition the Sherman Laboratory space into a set of modern, cutting-edge laboratories with faculty, students, and staff engaged in strategic and impactful research. And we see this transition as not just a physical or procedural change, but a paradigm shift towards a more comprehensive and evolving understanding of soil as a living system. 
    "It is also a commitment by CTAHR to always strive to be at the forefront of research and innovation, and to be consistent advocates for a scientific, data-driven approach that guides us in developing more sustainable, efficient, and resilient food systems while minimizing any negative impacts on the environment and society. In closing, we wish to emphasize that the transition outlined in this email only pertains to the ADSC analytical service labs in Sherman Laboratory [Manoa] for testing soil, plant tissue, forage, feed, and food. There are no impending changes 
     CTHAR's website notes the value of soil testing: "The importance of soils to crops was recognized long ago and knowing one’s soil continues to be an essential part of being a successful farmer today. It is quite remarkable that the Hawaiian Islands, a small group of islands over 2500 miles from the nearest continent and geologically very young, has soils belonging to all of the 11 soil orders known. Because rainfall has such an impact on soil development, and Hawai‘i’s rainfall can be so variable from one part of an island to another, the soils can be variable within a very short distance. Knowing, and understanding the soil type and characteristics of the soil is essential to managing the fertility of the soil and minimizing nutrient waste."
A minor ooze-out of lava in Halema'uma'u on June 22 on the northeast (bottom-right) margin of the recently erupted lava. This indicates that while no new lava is erupting, there is still minor lava circulation in places under the solidified crust. "This is expected as the recently dynamic system cools downs," says Hawaiian Volcano Observatory.
 USGS photo by N. Deligne

WHAT'S THE HIGHEST ELEVATION REACHED BY HALEMA'UMA'U LAVA? That is the question posed by this week's Volcano Watch, written by U.S. Geological Survey scientists and affiliates:
The 2018 collapse of southern Kaluapele (Kīlauea caldera) left a pit whose lowest point was about 500 m (1640 ft) above sea level (asl). Since 2020, that pit has filled to a little over 900 m (2950 ft) asl and one might wonder how high the lava level could go. We can't answer that question but we can get an idea by looking to Kīlauea's past.
     The history of Kaluapele is a collection of periods of rising lava level within Halemaʻumaʻu, often to the point of overflowing, followed by abrupt and rapid drops in the level. After some time, the sequence repeats, rising to a slightly higher level. The process resembles a "two steps forward, one step back" sequence, with slowly rising lava level peaks.
    The highest level of lava in the past two centuries was reached in the first few months of 1894, during years of repeat surveys by the Hawaiian Government. Rapid drops of the lava level occurred on March 6, 1886, and again exactly five years later on March 6, 1891. The final rapid drop of the 19th century began on July 11, 1894.
    Frank Dodge, a surveyor with the Hawaiian Government Survey, mapped Halemaʻumaʻu in August 1892 and March 1894. The 1892 survey showed a lava lake 73 m (240 ft) below the rim of Halemaʻumaʻu pit and 160 m (522 ft) below the Volcano House veranda on the northeast rim of the caldera (elevation 1231 m or 4040 ft asl), then located about 150 m (490 ft) northwest of the current hotel. Elevations were measured multiple times with a surveyor's theodolite to assure the highest accuracy possible. The lava level elevation was 1072 m (3518 ft) asl in August 1892.
    The lava level continued to rise and, in the first months of 1894, visitors and residents found that lava frequently overflowed from Halemaʻumaʻu onto the caldera floor. They also noted that the pit crater was filled, and the lava lake was "on top of a nearly circular cone" or hill.
   Dodge completed a follow-up map on March 20, 1894, confirming the filling of Halemaʻumaʻu pit and the rising of the lava lake above the 1891 pit rims. The lava lake was about 6 hectares (15 acres) in area atop a low shield on the caldera floor. Instead of multiple measures of elevation below the Volcano House, he only made one.
The 1894 map was excellent; however, Dodge's quick measurement of the lava lake elevation relative to the Volcano House may have been wrong. After completing the map in 1894, he stated that the lava level rose "447 ft in 19 months" since 1892; however, in 1904, he began to doubt that measurement and he added a note in the margin of this map saying that the 447 ft (136 m) change may be too high.
    Dartmouth Professor emeritus C.H. Hitchcock suggested a compromise: assume that, in March 1894, Halemaʻumaʻu was filled to the 1892 brim so the lava level rose by only 73 m (240 ft) between surveys. 

chart showing overlaid cross-sections of volcanic crater
Surveyor Frank Dodge's 1894 cross-section of Halema'uma'u overlaid on his 1892 cross-section.The 1892 lava lake
was measured at 73 m (240 ft) below the rim of Halema'uma'u pit and by early-1894, the lava lake had filled the pit
and frequently overflowed onto the caldera floor. The overlay of these two cross-sections shows a minimum
elevation of the 1894 lava lake. Image from USGS

This ignored multiple reports and Dodge's map of the lava lake being above the earlier rims.
Dodge responded that he could not accept Hitchcock's suggested solution. "The height of the lava at the 'supreme moment for Halemaumau' will never be positively known...It was somewhere between the -75' and -282', referred to the Volcano House datum" (between 1145 and 1209 m asl).
     In addition to the map, Dodge also drew August 1892 and March 1894 cross-sections of the Halemaʻumaʻu pit at the same scale. If we ignore the questionable datum line on the 1894 cross-section and overlay on the 1892 cross-section by matching slopes outside the pit, we can graphically estimate the highest elevation. This simple exercise shows that the March 1894 lake must have been at least 30 m (100 ft) above the 1892 brim. This all-time peak elevation was a minimum of 55 m (180 ft) below the Volcano House veranda or 1177 m (3860 ft) asl.
    For perspective, the 2008–2018 5 hectare (12 acre) lava lake rose to 1034 m (3392 ft) asl just before its final drop during the 2018 summit collapse. The 2018 Halemaʻumaʻu pit crater (150 hectares or 370 acres) is currently filled to about 920 m (30 20 ft) asl.
We have a long way to go to reach a new "supreme moment" for Halemaʻumaʻu.
Looking southwest across the Halemaʻumaʻu crater floor within the Kīlauea summit caldera, captured during a helicopter overflight on Thursday, June 22, 2023. Lava erupted during the most recent eruption comprises the crater floor in the bottom half of the photo. Remnants of the main island—formed during the early stages of the December 20, 2020 eruption—protrude above the cooled lava lake in the center of the photo, and the recent eruptive vent on the southwest wall of Halemaʻumaʻu is visible behind and right of the main island. USGS photo by N. Deligne

Volcano Activity Updates: Kīlauea's eruption is paused. Its USGS Volcano Alert level is WATCH.
The summit eruption at Kīlauea volcano—which has been confined to Halemaʻumaʻu crater—is paused, following a rapid decline in vent and lava lake activity in the afternoon of Monday, June 19. Simultaneously, seismometers detected a decline in eruptive tremor while tiltmeters began tracking gradual inflation that continues at this time. Volcanic gas emissions in the eruption area have dropped; a sulfur dioxide (SO2) emission rate of approximately 175 tonnes per day was measured on Wednesday, June 21, with this rate being a fraction of those measured before the eruptive pause.
Mauna Loa is not erupting. Its USGS Volcano Alert Level is at NORMAL.
Webcams show no signs of activity on Mauna Loa. Seismicity remains low. Summit ground deformation rates indicate slow inflation as magma replenishes the reservoir system following the recent eruption. SO2 emission rates are at background levels.
There was one earthquake with 3 or more felt reports in the Hawaiian Islands during the past week: a M2.5 earthquake near the Kīlauea summit at 0 km (0 mi) depth on June 19 at 6:56 p.m. HST.