1. Draft volcano primer: Mt. Pinatubo and Taal volcanoes, the Philippines

3. Mt. PINATUBO ERUPTIONS June 1991

4. Prior to eruption

5. Fumaroles on flanks, April 1991

6. June 12th, 1991 eruption

7. Giant pyroclastic flows, June 15th 1991 form off of collapsing eruption column

8. The view from space via the Japanese GMS-5 geostationary satellite

9. Early effects on the ground

10. Sediment-laden rivers destroy roads & bridges

11. Major landscape changes: Pyroclastic flows in-filled pre-existing river valleys (the peaks in two views below are the same feature)

12. AIR PHOTOS (recent views)

13. Summit caldera of Mt. Pinatubo, Nov. 1999. The low-point in the rim is a future hazard as the lake will eventually over-top here.

14. Typical view of eastern flank, Nov. 1999

15. Erosion of ignimbrite fan on NW. flank, November 1999

16. Erosion of river valley on the northern flank, Nov. 1999

17. Sediment fills valley floor downslope on lower E. flank November 1999

18. Detail of lahar-filled valley E. flank, Nov. 1999

19. GROUND PHOTOS

20. Exploring eroded valley, SW flank Nov. 1999

21. Crossing the sediment-laden streams is a real challenge! So much sediment is in these streams that they easily knock you over.

22. Valley erosion can be extreme in places: Up to 20 m down-cutting during one typhoon! This mosaic shows the remains of the 1991 deposit (white unit) that has been cut by younger flash floods

23. Erosion of 1991 deposit

24. Vegetation is starting to grow back on western fan. Summit of Mt. Pinatubo in background

25. “LAHARS” (MUDFLOWS) AND THE RESULTANT DAMAGE

26. Major changes in valley floor elevation after single lahar has formed after typhoon.

27. The impact on villages within the path of a lahar can be extreme

28. While old houses are buried, new homes are built on stilts to try to avoid the next lahar

29. An old church has been partially-buried so that you now enter on the 2nd floor. Ronnie Torres shows the church prior to the lahars.

30. Giant dikes made from old lahar and covered with concrete now try to protect areas from new lahars

31. The contrast between areas protected by the dikes and unprotected is striking -- and it’s all an issue of insurance for redevelopment!

32. Some homes, once buried by lahar, and now being exposed by recent erosion

33. REMOTE SENSING DATA

34. Landsat 7 Path 116 Row 50

35. RADARSAT radar backscatter image of Mt. Pinatubo, February 1998

36. SPOT image of Mt. Pinatubo December 1991

37. Comparison of NW Summit from SPOT data obtained between 1991 and 1998 Red shows vegetation, the ash deposits are light blue Summit is at lower right

38. Changes in Mt. Pinatubo lahar deposits. Lower Pasig-Potrero River 1991 - 1996

39. TAAL VOLCANO (just south of Manila)

41. RADARSAT scansar beam 1 (50 m/pixel) image of Taal Volcano and surrounding area

42. View of Lake Taal and Volcano Island from north rim, Nov. 1999

43. NW corner of Lake Taal

44. Over 4,000 people live without permission on the shores of Volcano Island

45. In the event of an eruption of Taal, all the population would have to leave Volcano Island via small boats

46. View of the volcanic lake in middle of Volcano Island (middle of Lake Taal)

47. In Fall 1999, this vent on Volcano Island was actively geysering.

48. Close-up view of recently active vent on Volcano Island, in the middle of Taal Volcano

49. Even around the rim of Lake Taal, people and their fish farms are at risk from tsunamis generated by eruptions.