POTENTIAL IMPACT ON WATER RESOURCES FROM ERUPTIONS NEAR MAMMOTH LAKES, MONO COUNTY, CALIFORNIA <ul><ul><li>R. Forrest Hops...
INTRODUCTION <ul><li>Concerns for renewed volcanism was prompted by </li></ul><ul><li>Increased seismicity beneath the sou...
TOPICS OF DISCUSSION <ul><li>Explore possible scenarios for volcanic eruptions.  </li></ul><ul><li>Describe possible hazar...
PURPOSE <ul><li>Assess the potential impact of eruptions on water resources near Mammoth Lakes. </li></ul><ul><li>Specific...
PREVIOUS WORK <ul><li>Impact on Water Quality </li></ul><ul><li>Blong 1984 </li></ul><ul><li>Hopson 1991 </li></ul><ul><li...
Generalized map of the Mammoth Lakes region.
Long Valley Caldera from summit of White Mountain Peak.
Mammoth Mountain from Deer Mountain.
Inyo-Mono Craters Volcanic Chain from the summit of Mammoth Mountain.
Geologic Overview Simplified geologic map of the Mammoth Lakes region.  Source: U.S. Geological Survey
Lake Crowley and south moat of Long Valley caldera.
POSSIBLE ERUPTION SCENARIOS <ul><li>Small- to moderate eruptions (0.1 to 1 km 3 ) of magma  </li></ul><ul><li>Phreatic pha...
POSSIBLE ERUPTION SCENARIOS <ul><li>Small- to moderate eruptions (0.1 to 1 km 3 ) of magma  </li></ul><ul><li>Phreatic pha...
Inyo Craters from the summit of Deer Mountain.
POSSIBLE ERUPTION SCENARIOS <ul><li>Small- to moderate eruptions (0.1 to 1 km3) of magma  </li></ul><ul><li>Phreatic phase...
POSSIBLE ERUPTION SCENARIOS  <ul><li>Small- to moderate eruptions (0.1 to 1 km 3 ) of magma  </li></ul><ul><li>Phreatic ph...
Mono-Inyo Craters Volcanic Chain from the summit of Deer Mountain.
POSSIBLE ERUPTION SCENARIOS <ul><li>Small- to moderate eruptions (0.1 to 1 km 3 ) of magma  </li></ul><ul><li>Phreatic pha...
Cinder Cone and Butte Lake, Lassen Volcanic National Park.
Mono-Inyo Craters Volcanic Chain from the summit of Mammoth Mountain. POTENTIALLY HAZARDOUS  VOLCANIC EVENTS
A model showing the dike that triggered the eruptive events from the Mono-Inyo Craters chain 650–550 years ago.  Illustrat...
POTENTIALLY HAZARDOUS VOLCANIC EVENTS  <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul><ul><li>A...
POTENTIALLY HAZARDOUS VOLCANIC EVENTS <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul><ul><li>Ai...
POTENTIALLY HAZARDOUS VOLCANIC EVENTS <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul><ul><li>Ai...
Source: map from C. D. Miller, modified by J. Johnson (U.S. Geological Survey).
Ash and pumice layer from the May 18, 1980 eruption of Mt. St. Helens. Layer is about 15 cm thick.
POTENTIALLY HAZARDOUS VOLCANIC EVENTS <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul><ul><li>Ai...
Source: map from C. D. Miller, modified by J. Johnson (U.S. Geological Survey).
POTENTIALLY HAZARDOUS VOLCANIC EVENTS <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul><ul><li>Ai...
Smith Creek lahar from the May 18, 1980 eruption of Mt. St. Helens.
POTENTIALLY HAZARDOUS VOLCANIC EVENTS <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul><ul><li>Ai...
ASSESSMENT OF POSSIBLE IMPACT ON WATER RESOURCES <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul...
Lava Domes and Flows <ul><li>Little impact on water quality  </li></ul><ul><li>Pipelines in path of advancing lava flows m...
Butte Lake and Fantastic Lava Beds from Cinder Cone, Lassen Volcanic National Park.
Volcanic Ash <ul><li>Increase in turbidity </li></ul><ul><li>Increase in acidity  </li></ul><ul><li>Short-term chemical ch...
Pyroclastic Flows and Surges   <ul><li>All of the above </li></ul><ul><li>Clog stream channels  </li></ul><ul><li>Melt sno...
Lahars, Floods, and Debris Avalanches  <ul><li>Lahars could block and change morphology of stream channels and deposit mas...
Coldwater Lake debris dam, Mt. St. Helens National Volcanic Monument.
DISCUSSION Lake Crowley from the summit of Glass Mountain
CONCLUSIONS <ul><li>Streams might be displaced from their channels by advancing flows or growing domes </li></ul><ul><li>T...
CONCLUSIONS cont’d <ul><li>Temporary minor changes in water composition from leaching of volcanic ash or sediment </li></u...
The End
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Hopson 2001 Potential Impact On Water Resources From Eruptions Near Mammoth Lakes Aeg Talk

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Presentation for a AEG-Great Basin Section delivered May 2003

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Hopson 2001 Potential Impact On Water Resources From Eruptions Near Mammoth Lakes Aeg Talk

  1. 1. POTENTIAL IMPACT ON WATER RESOURCES FROM ERUPTIONS NEAR MAMMOTH LAKES, MONO COUNTY, CALIFORNIA <ul><ul><li>R. Forrest Hopson </li></ul></ul><ul><ul><li>Geological Information Services </li></ul></ul><ul><ul><li>Reno, Nevada </li></ul></ul><ul><ul><li>[email_address] </li></ul></ul>
  2. 2. INTRODUCTION <ul><li>Concerns for renewed volcanism was prompted by </li></ul><ul><li>Increased seismicity beneath the south moat of Long Valley caldera </li></ul><ul><li>Uplift of the caldera floor </li></ul><ul><li>Increased hot spring activity </li></ul><ul><li>CO 2 emission near Lake Mary (early 1990s) </li></ul>
  3. 3. TOPICS OF DISCUSSION <ul><li>Explore possible scenarios for volcanic eruptions. </li></ul><ul><li>Describe possible hazards from these eruptions. </li></ul><ul><li>Explain why they can be expected. </li></ul><ul><li>Discuss the impact on surface water, including the Los Angeles-Owens River Aqueduct. </li></ul>
  4. 4. PURPOSE <ul><li>Assess the potential impact of eruptions on water resources near Mammoth Lakes. </li></ul><ul><li>Specifically, the impact on surface water quality and water distribution systems, including the Los Angeles-Owens River Aqueduct. </li></ul>
  5. 5. PREVIOUS WORK <ul><li>Impact on Water Quality </li></ul><ul><li>Blong 1984 </li></ul><ul><li>Hopson 1991 </li></ul><ul><li>Hopson 2001 </li></ul><ul><li>Mammoth Lakes Geology </li></ul><ul><li>Bailey 1989 </li></ul><ul><li>Miller et al 1982 </li></ul><ul><li>Ewert & Harpel 2000 </li></ul>
  6. 6. Generalized map of the Mammoth Lakes region.
  7. 7. Long Valley Caldera from summit of White Mountain Peak.
  8. 8. Mammoth Mountain from Deer Mountain.
  9. 9. Inyo-Mono Craters Volcanic Chain from the summit of Mammoth Mountain.
  10. 10. Geologic Overview Simplified geologic map of the Mammoth Lakes region. Source: U.S. Geological Survey
  11. 11. Lake Crowley and south moat of Long Valley caldera.
  12. 12. POSSIBLE ERUPTION SCENARIOS <ul><li>Small- to moderate eruptions (0.1 to 1 km 3 ) of magma </li></ul><ul><li>Phreatic phase </li></ul><ul><li>Explosive magmatic phase </li></ul><ul><li>Effusive phase </li></ul><ul><ul><li>Dome-building eruptions </li></ul></ul><ul><ul><li>Cinder cone eruptions </li></ul></ul>
  13. 13. POSSIBLE ERUPTION SCENARIOS <ul><li>Small- to moderate eruptions (0.1 to 1 km 3 ) of magma </li></ul><ul><li>Phreatic phase </li></ul><ul><li>Explosive magmatic phase </li></ul><ul><li>Effusive phase </li></ul><ul><ul><li>Dome-building eruptions </li></ul></ul><ul><ul><li>Cinder cone eruptions </li></ul></ul>
  14. 14. Inyo Craters from the summit of Deer Mountain.
  15. 15. POSSIBLE ERUPTION SCENARIOS <ul><li>Small- to moderate eruptions (0.1 to 1 km3) of magma </li></ul><ul><li>Phreatic phase </li></ul><ul><li>Explosive magmatic phase </li></ul><ul><li>Effusive phase </li></ul><ul><ul><li>Dome-building eruptions </li></ul></ul><ul><ul><li>Cinder cone eruptions </li></ul></ul>
  16. 16. POSSIBLE ERUPTION SCENARIOS <ul><li>Small- to moderate eruptions (0.1 to 1 km 3 ) of magma </li></ul><ul><li>Phreatic phase </li></ul><ul><li>Explosive magmatic phase </li></ul><ul><li>Effusive phase </li></ul><ul><ul><li>Dome-building eruptions </li></ul></ul><ul><ul><li>Cinder cone eruptions </li></ul></ul>
  17. 17. Mono-Inyo Craters Volcanic Chain from the summit of Deer Mountain.
  18. 18. POSSIBLE ERUPTION SCENARIOS <ul><li>Small- to moderate eruptions (0.1 to 1 km 3 ) of magma </li></ul><ul><li>Phreatic phase </li></ul><ul><li>Explosive magmatic phase </li></ul><ul><li>Effusive phase </li></ul><ul><ul><li>Dome-building eruptions </li></ul></ul><ul><ul><li>Cinder cone eruptions </li></ul></ul>
  19. 19. Cinder Cone and Butte Lake, Lassen Volcanic National Park.
  20. 20. Mono-Inyo Craters Volcanic Chain from the summit of Mammoth Mountain. POTENTIALLY HAZARDOUS VOLCANIC EVENTS
  21. 21. A model showing the dike that triggered the eruptive events from the Mono-Inyo Craters chain 650–550 years ago. Illustration from J.H. Fink and modified by J. Johnson Photograph by S.R. Brantley on August 2, 1998.
  22. 22. POTENTIALLY HAZARDOUS VOLCANIC EVENTS <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul><ul><li>Airfall ash </li></ul></ul><ul><ul><li>Pyroclastic flows and surges </li></ul></ul><ul><li>Lahars and Floods </li></ul><ul><li>Debris Avalanches </li></ul>
  23. 23. POTENTIALLY HAZARDOUS VOLCANIC EVENTS <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul><ul><li>Airfall ash </li></ul></ul><ul><ul><li>Pyroclastic flows and surges </li></ul></ul><ul><li>Lahars and Floods </li></ul><ul><li>Debris Avalanches </li></ul>
  24. 24. POTENTIALLY HAZARDOUS VOLCANIC EVENTS <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul><ul><li>Airfall ash </li></ul></ul><ul><ul><li>Pyroclastic flows and surges </li></ul></ul><ul><li>Lahars and Floods </li></ul><ul><li>Debris Avalanches </li></ul>
  25. 25. Source: map from C. D. Miller, modified by J. Johnson (U.S. Geological Survey).
  26. 26. Ash and pumice layer from the May 18, 1980 eruption of Mt. St. Helens. Layer is about 15 cm thick.
  27. 27. POTENTIALLY HAZARDOUS VOLCANIC EVENTS <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul><ul><li>Airfall ash </li></ul></ul><ul><ul><li>Pyroclastic flows and surges </li></ul></ul><ul><li>Lahars and Floods </li></ul><ul><li>Debris Avalanches </li></ul>
  28. 28. Source: map from C. D. Miller, modified by J. Johnson (U.S. Geological Survey).
  29. 29. POTENTIALLY HAZARDOUS VOLCANIC EVENTS <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul><ul><li>Airfall ash </li></ul></ul><ul><ul><li>Pyroclastic flows and surges </li></ul></ul><ul><li>Lahars and Floods </li></ul><ul><li>Debris Avalanches </li></ul>
  30. 30. Smith Creek lahar from the May 18, 1980 eruption of Mt. St. Helens.
  31. 31. POTENTIALLY HAZARDOUS VOLCANIC EVENTS <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul><ul><li>Airfall ash </li></ul></ul><ul><ul><li>Pyroclastic flows and surges </li></ul></ul><ul><li>Lahars and Floods </li></ul><ul><li>Debris Avalanches </li></ul>
  32. 32. ASSESSMENT OF POSSIBLE IMPACT ON WATER RESOURCES <ul><li>Lava Domes and Flows </li></ul><ul><li>Volcanic Ash </li></ul><ul><li>Pyroclastic Flows and Surges </li></ul><ul><li>Lahars, Floods, and Debris Avalanches </li></ul>
  33. 33. Lava Domes and Flows <ul><li>Little impact on water quality </li></ul><ul><li>Pipelines in path of advancing lava flows may be destroyed </li></ul><ul><li>Lava flows may impede stream flow and create large lakes </li></ul><ul><li>Greatest danger would be from pyroclastic flows or debris avalanches </li></ul>
  34. 34. Butte Lake and Fantastic Lava Beds from Cinder Cone, Lassen Volcanic National Park.
  35. 35. Volcanic Ash <ul><li>Increase in turbidity </li></ul><ul><li>Increase in acidity </li></ul><ul><li>Short-term chemical changes from leaching of newly erupted ash </li></ul><ul><li>Change in ablation rates </li></ul><ul><ul><li>Ash layers >24 mm would slow ablation rates </li></ul></ul><ul><ul><li>Thin ash layers would increase ablation </li></ul></ul>
  36. 36. Pyroclastic Flows and Surges <ul><li>All of the above </li></ul><ul><li>Clog stream channels </li></ul><ul><li>Melt snow and ice that could trigger lahars, debris flows, and floods </li></ul><ul><li>Clog filters, pumps, and pipes in water intakes and distribution systems along the LAORA </li></ul><ul><li>Damage turbines in power plants </li></ul>
  37. 37. Lahars, Floods, and Debris Avalanches <ul><li>Lahars could block and change morphology of stream channels and deposit massive volumes of sediment </li></ul><ul><li>Public water supply systems would be vulnerable to lahars and flood </li></ul><ul><li>Changes in chemistry from the leaching of mud </li></ul>
  38. 38. Coldwater Lake debris dam, Mt. St. Helens National Volcanic Monument.
  39. 39. DISCUSSION Lake Crowley from the summit of Glass Mountain
  40. 40. CONCLUSIONS <ul><li>Streams might be displaced from their channels by advancing flows or growing domes </li></ul><ul><li>Temporary increase in acidity and turbidity from volcanic ash, lahars, or debris avalanches </li></ul><ul><li>Voluminous pyroclastic flows, lahars, and debris avalanches might do two things: </li></ul><ul><ul><li>Impound streams channels, causing water to back up behind the debris dam. Failure of the dam would cause massive flooding downstream. </li></ul></ul><ul><ul><li>Deposited in Lake Crowley or Mammoth Pool Reservoir which could displace water causing it to overtop and possibly damage the dam </li></ul></ul>
  41. 41. CONCLUSIONS cont’d <ul><li>Temporary minor changes in water composition from leaching of volcanic ash or sediment </li></ul><ul><li>Less snowmelt runoff if thick ash layers were to accumulate over snow. </li></ul><ul><li>Water intake structures and conveyance systems along the LAORA could get clogged and buried by large pyroclastic flows, lahars, and debris avalanches </li></ul>
  42. 42. The End

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