The 50 state deepest hole list can still be improved. Any improvements or corrections are welcome, and some tips for this work are at bottom. Thanks - Andy Martin oldadit @ iname.com Mike Schwartz leads the race to the bottom with AZ in 1962, plus NJ, FL, GA, NY and DE in 2007. He plans to complete the project in AK with a fiery leap into the Korovin volcano. DRAFT - 50 STATE SUBSIDENCE LEADERS - DRAFT Compiled May 2007 by Andy Martin with contributions from Mike Beavers, Jerry Brekhus, Edward Earl, Paul Klenke, David Metzler, Carl Mills, John Mitchler, Ken Oeser, David Olson, John Roper, Roger Rowlett, Mike Schwartz, Ron Tagliapietra, Dave Unger, and Clifford Young. Subsidence: Elevation difference between a depression and the highest contour that encircles it and no lower locality. ST DEPRESSION QUAD SUBSIDENCE SADDLE SADDLE QUAD CA Saline Valley Craig Canyon 3,860 +50 4,920 +40 Harris Hill or White Top Mtn. NV Humboldt Salt Marsh Humb. S. Marsh 1,420 +50 4,800 +40 Denio Summit UT Pine Valley Hardpan Pine Val. H. N. 805 +40 5,880 +40 Middle Mountain AK Korovin Volcano Atka 1:250,000 800 +400 4,200 +200 Atka 1:250,000 OR Summer Lake Summer Lake 600.5 4,747.5 Sawed Horn TX "Salt Basin" Figure Two Ranch 596 +40 4,160 +40 Ninetysix Ranch HI Puhimau Crater Kilauea Crater 520 +40 3,620 +20 Kilauea Crater AZ Meteor Crater Meteor Crater 497 +20 5,620 +20 Meteor Crater NM Laguna del Perro Laguna del Perro 300 +20 6,340 +10 Pino Mountain or NM Plains of San Augus. Rael Spring 303 +5 7,078 Tres Montosas WV 1 mile west of Alta Asbury 280 +40 2,220 +20 Asbury WA Omak Lake Omak Lake 250 1,205 Omak Lake or near Bare Mountain Bare Mountain 200 +80 4,040 +40 Bare Mountain CO Dotsero Crater Dotsero 242 +40 7,000 +40 Dotsero ID Crater Rings Crater Rings 223 +20 3,180 +20 Crater Rings TN Wolf Cove Pitcher Ridge 220 +40 1,200 +20 Pitcher Ridge KY 1 m. w. Violet City Mammoth Cave 180 +40 660 +20 Mammoth Cave WY Separation Lake Rendle Hill 160 +40 6,540 +20 Rawlins NW VA Sinking Creek Dungannon 140 +40 1,540 +20 Dungannon AL Fricks Cove Langston 140 +40 1,140 +20 Langston 1984 or AL Calloway Sinks Hollytree 140 +40 1,100 +20 Hollytree MO Forty Acre Sinkhole Summersville NE 140 +40 1,120 +20 Summersville NE or MO The Sinks Siloam Springs 140 +40 1,020 +20 Siloam Springs 1973 FL Devils Mill Hopper Gainesville West 120 +5 175 +5 Gainesville West WI 1/2 mile WSW of Rib Lake Moquah 110 +20 1,310 +10 Moquah 1975 MI 3/4 mi. SW of Second Lake Oak Lake 100 +10 1,250 +10 Oak Lake 1986 MN in 6-60N-21W Side Lake 90 +20 1,460 +10 Side Lake MT Nelson Lake Boulder Peak 80 +80 7,360 +40 Boulder Peak or 1/2 mile NW of Cliff Mtn Amphit. Mtn. 80 +80 7,760 +40 Amphitheatre Mtn. MA 1.25 m. W. Clam Pudding Pond Manomet 70 +20 150 +10 Manomet 1977 NY 2 miles north of Twin Ponds Middle Island 70 +20 120 +10 Middle Island 1967 NE Big Swede Valley Wild Horse Hill 60 +40 3,860 +20 Wild Horse Hill 1986 NH The Hoppers, 2 areas Dover West 60 +40 200 +20 Dover West ND 3/4 m. E Smoky Butte Smoky Butte 60 +20 2,060 +10 Smoky Butte 1948 ME 1000' NE of Myers Ponds Epping 55 +10 260 +10 Epping 1984 or ME Myers Ponds Epping 48 +10 260 +10 Epping 1984 or .5 m. SW Coffin Brook Pond Epping 48 +10 220 +10 Epping 1984 or 1/4 m. S. of Tyler Pond Belgrade 40 +20 310 +10 Belgrade 1980 KS Little Basin Ashland NW 50 +20 2,270 +10 Ashland NW SD Bradley St. Pub. Shoot. Ar. Heggs Lake 50 +20 1,780 +10 Heggs Lake 1973 IN .3 mi. west of Hamer Cave Mitchell 50 +20 660 +10 Mitchell IL .4 mi. west of New Hanover Columbia 50 +20 550 +10 Columbia CT .5 mile S. of Mustard Bowl Hartford South 50 +20 130 +10 Hartford South 1992 AR big area .8 mi. E. co. line Onia 40 +40 1,020 +20 Onia 1972 VT 3/4 mi. NNE Lake Shaftsbury Arlington 40 +40 960 +20 Arlington 1997 PA The Sink Montoursville S. 40 +40 640 +20 Montoursville South 1994 NJ 3/4 mi. SW of Swartswood St. Newton West 40 +40 500 +20 Newton West 1994 OK 27-1N-4E Boise City SE 33 +5 4,195 +5 Boise City SE OK/TX NC 3/4 mile east of Mann Point Manteo 30 +20 40 +10 Manteo 1983 GA 3/4 mi. E. of St. Marks Ch. Vada 30 +10 130 +5 Vada 1983 OH 1 mile SE of Castalia Castalia 25 +10 680 +5 Castalia 1969 MD small hole on Martin Mtn. Evitts Creek 20 +40 1,720 +20 Evitts Creek MD/PA/WV 1974 IA Maquoketa Caves State Park Baldwin 20 +40 820 +20 Baldwin RI 2 areas in Rodman Hollow Block Island 20 +20 70 +10 Block Island SC 3 miles north of Barnwell Blackville 20 +20 230 +10 Blackville LA 2 nearby ponds, 7-19N-14E Eagle Bend 15 +10 95 +5 Eagle Bend LA/MS 1994 MS 3/4 mile SW of Longwood Avon 10 +10 110 +5 Avon 1970 DE 1/4 mi. SE Ebenezer Cem. Fairmont 10 +10 30 +5 Fairmont 1984 Possibly tie or exceed values above. AR The Basin Marshall 20 +40 1,020 +20 Marshall 1926 CT 2 areas 1 mi. east of Avon Avon 30 +30 260 +10 Avon 1984 GA 2 ar. 1 m. W Kinchafoonee Ch. Leesburg 20 +20 230 +10 Leesburg 1988 KS 6 miles east of Dry Lake Amy SW 45 +10 2,860 +5 Amy SW 1974 LA 1 small pond, 28-20N-13E Fitler 15 +10 100 +5 Fitler LA/MS 1994 LA west of Cottonwood Chute Lake Providence 10 +10 100 +5 Lake Providence LA/MS MA 2 ar. 1/2 mi. from Air Force Sta. North Truro 60 +20 140 +10 North Truro 1972 MD 0.1 mi. SE Rush Ch. Flintstone 20 +40 1,120 +20 Flintstone MD/PA MD 1 mi. N. of Ridgely Denton 6 +20 60 +20 Denton 1973 NJ 0.1 mi. S of Punch Bowl Road Morristown 40 +40 380 +20 Morristown OH 1 mile west of Reeds Higginsport 0 +40 500 +20 Higginsport OH/KY 1974 OH assume manmade: 1.5 mi. SE York Free Chapel Clyde 25 +10 770 +5 Clyde 1969 OK 36.712 N 102.344 W Sampsel Lake 30 +15 3,980 +5 Sampsel Lake OK 36.513 N 102.575 W Boise City SE 30 +10 4,150 +5 Boise City SE OK/TX WY The Big Hollow Miller 150 +20 7,260 +10 Laramie SW 1978 Former listings, discarded after improved listings were found AL on Horton Mountain Masterson 40 +20 710 +10 Masterson FL sec. 21-22S-26E Clermont East 95 +10 245 +5 Clermont East KS 1-19S-32W Tractor 15 +10 2,965 +5 Tractor ME Tyler Pond Belgrade 39 +10 300 +10 Belgrade ME 2 ar. W. of The Whaleback Amherst 20 +20 270 +20 Amherst 1988 ND 7 (?) areas Camp Grafton 5 +10 varies +5 Camp Grafton NE "Merna Crater" Callaway NW 40 +20 2,970 +10 Callaway NW NH 1/2 mi. W. of Millstone Hill Center Harbor 20 +40 560 +20 Center Harbor 1998 NY 4 m. N. of Effley Falls Pond Belfort 40 +20 1,340 +10 Belfort 1966 SC 1/4 mi. W. of Beeswax Bay Hartsville South 0 +20 210 +10 Hartsville South 1968 SD Salt Lake Gary NW SD/MN 8 +10 1,150 +10 Gary NW MN/SD TN Grassy Cove Grassy Cove 140 +40 1,660 +20 Grassy Cove 1976 TN Round Cove Sinking Cove 80 +40 1,000 +20 Sinking Cove NC 1/2 mi. NW of Saint Paul Ch. Saint Pauls 0 +10 150 +5 Saint Pauls 1997 WA south of Frenchman Coulee Evergreen Ridge ?160 +20 850 +10 Evergreen Ridge WA Hudson Coulee Coulee City 140 +20 1,410 +10 Coulee City WA Carp Lake White Pine B. 128 +40 2,600 +40 White Pine Buttes WA Crater Lake Boundary Dam 127 +40 4,600 +40 Boundary Dam WA Spirit Lake outlet Spirit Lake West 120 +80 3,520 +40 Spirit Lake West WA East Crater Gifford Peak 80 +80 5,080 +40 Gifford Peak WI 1/2 mi. SE Walnut Grove Cem. Elkhart Lake 70 +20 1,040 +10 Elkhart Lake 1992 THE HOLE STORY by Andy Martin INTRODUCTION Low Points have attracted comparatively subdued interest when compared to their high point "cousins". The traditional western state sumps (per USGS) are a motley collection of 8 state liners, 4 ocean beaches, and only one point of interest, Death Valley. However, applying a concept similar to Prominence, which is dubbed "Subsidence" at present, lets us identify the deepest basins in these states. Sessions in the map library and contributions from many map geeks have yielded a draft list, which serves as a starting point for further work. DEFINITION AND EXPLANATION Subsidence is basically just a way of measuring basin depth, from the bottom to the overflow saddle. Prominence is often explained by a Noah's flood example, so lets use a similar line of reasoning, the Super Spring. Place this bountiful water source at the bottom of the basin in question, and fill it until the resulting lake drains over a saddle. If it drains into a deeper basin, Subsidence is simply the water depth over the Super Spring. However, if drainage was into a higher basin, raise the lake to the next "key saddle" and repeat the analysis. As a side note, I believe every basin has a unique key saddle, and every saddle is key either for a basin or a peak. CAVERNS AND MINES Underground and surface mines are eliminated as manmade. However, it is interesting to note that while the greatest manmade towers are greatly overshadowed by mountain heights, the deepest mines, say 2 miles deep from shaft collar, are world records if compared with natural basins. Our study is restricted to mapped contour lines, thus only large mapped sinkholes are eligible for inclusion. Note that in many states the deepest cave would exceed the listed subsidence leader. Also note that contours are sometimes left off sinkhole bottoms. Mexico boasts a sinkhole deep enough to parachute into, but it is unlikely the bottom is mapped. HOLE CREATION Just as there are many ways mountains are made, we can list several ways nature makes holes: 1. Basin/Range faulting 2. Volcanic craters and fissures 3. Volcanic collapse calderas 4. Glacial cirques 5. Glacial kettles and moraines 6. Meteor impact 7. Low areas between sand dunes 8. Landslide dams 9. Sinkholes in Limestone 10. Rift valleys Dry climates are useful, to bail out water accumulations. Similarly, porous karst or boulder fields are handy for sneaking water out of would-be lakes. BASIN BAGGING Summit seekers who branch out to basins will need to alter their habits. Building a cairn and hopping on top is counterproductive. Now they must dig a hole and touch bottom to snag the pit, or perhaps aim for total submersion in water filled basins. Fame and renown are missing at present, and there is no race to be first to tame the 7 sumps. There is considerable danger in descending some volcanic and limestone holes. Many of these have never (and will never ?) seen a free climbing descent, as the temptation to simply rappel down is too hard to resist. FUTURE WORK The coarseness of gridded elevation data limits the value of computer searches for basins by Edward Earl's Winprom program, and manual searches are laborious. Thus we may never identify the best basins for the fifty states. However, I'd be interested in updating the list as deeper holes are found. Note that ties are not being listed for states with depressions less than 100 feet deep. However I will list ties for the 100'+ deep holes. Please send data to me at oldadit@iname.com. TRENCH TRIVIA CA: Death Valley (2202+ 40) comes to mind as the CA super sump, but the little known Saline Valley is nearly twice as deep, and may be in the bottom 10 on a global scale. Indeed, were the valley to fill to the rim, it would be the planets third deepest lake, trailing only Baikal (5,315') and Tanganyika (4,823'). NV: There are countless basins in NV. Were we to list all 300'+ subsidence spots [the hole "summit" list] in NV, it likely would lead the lower 48. AK: Given the uncertain depths of volcanic necks and poor maps in the Aleutians, there is considerable uncertainty as to Alaska's number 1 hole. HI: The Puhimau crater is a most impressive pit right off a paved road. Not too many tourists make it to the bottom - alive. A first descent possibility ? Moon: Newton Crater is reported to be 29,000 feet deep. [extra] HOLE HUNTING In most states east of the Rockies searching for the biggest hole in a state is a tough task. The brute force approach involves looking at every quad for the state, and this is possible for smaller states. However this would take a great deal of time in the larger states, and has not been done. It is also possible to just flip through some quads looking for a depression. When one is found the 7.5 quad is looked at in some detail, and the corresponding 1:100,000 sheet is pulled. Depressions that show up on the 1:100,000 maps are usually worth checking out in eastern states. The 1:100,000 quads will often help you identify karst areas, and also recent or fossil sand dunes. Another approach is to use the GNIS data on topozone. GNIS basins are often depressions, and with topozone you can quickly see how deep they are. When likely holes are spotted the 7.5 and 1:100,000 sheets can be pulled as needed. Several of the eastern state leaders were discovered this way. However, if a basin is not named it will not show up on GNIS. In addition, certain states like NC, SC, and NE have so many basins that all were not checked. Also, topozone allows searching on the initial letters of a feature. Searching on "sink" or "sunk" is handy for listing features like "sinking creek" or "sunkenlands". Another way of looking for karst terrain is to find caves on Google, and then look at the 7.5 quad in the area of the cave. ----------------------------------------------------------------------------