Sources and method

The facts and their sources

1. Þingvellir National Park places Silfra in the rift valley between the North American plate and the Hreppar microplate. www.thingvellir.is, read 6 Nov
2. The park calls Silfra a popular diving location and a major spring of the area. www.thingvellir.is, read 6 Nov
3. The park says the Þingvellir area sits on the plate boundaries of the Mid-Atlantic Ridge. www.thingvellir.is, read 6 Nov
4. Within the national park, diving and snorkeling are allowed in two fissures only: Silfra and Davíðsgjá. www.thingvellir.is, read 6 Nov
5. The park requires divers to hold a dry suit qualification or to have made at least 10 dry suit dives in the last two years. www.thingvellir.is, read 6 Nov
6. The park does not allow diving in a wetsuit. www.thingvellir.is, read 6 Nov
7. The park forbids diving alone, cave diving and going below 18 metres. www.thingvellir.is, read 6 Nov
8. The park says divers go entirely at their own responsibility and risk. www.thingvellir.is, read 6 Nov
9. The park says companies answer fully for those who dive under their guidance. www.thingvellir.is, read 6 Nov
10. Every dive and snorkel in Silfra must be registered; individuals also sign a liability statement and pay a visitor fee. www.thingvellir.is, read 6 Nov
11. The park does not supply diving or snorkeling gear. www.thingvellir.is, read 6 Nov
12. The park charges 1,000 ISK to park a car with five seats or fewer. www.thingvellir.is, read 6 Nov
13. Visit Iceland says Silfra is the one place in the world to dive between the North American and Eurasian plates. www.visiticeland.com, read 6 Nov
14. Visit Iceland says the plates drift apart and widen the ravine by about 2 cm a year. www.visiticeland.com, read 6 Nov
15. Visit Iceland says you can explore under water without a diver's licence, on trips for physically fit snorkelers. www.visiticeland.com, read 6 Nov
16. Dive.is gives a water temperature of 2 to 4 °C all year. www.dive.is, read 6 Nov
17. Dive.is says there is no best or worst time to go. www.dive.is, read 6 Nov
18. Dive.is puts Silfra about 60 km from Reykjavik, a little under an hour by car in good conditions. www.dive.is, read 6 Nov
19. Dive.is divides the main part of Silfra into four sections: Big Crack, Hall, Cathedral and Lagoon. www.dive.is, read 6 Nov
20. Dive.is says the first three sections are deep canyons, and that the last is a shallow lagoon, full of algae, about 100 m across. www.dive.is, read 6 Nov
21. Dive.is gives the whole rift a surface of about 600 by 200 metres. www.dive.is, read 6 Nov
22. Dive.is says a cave beside the entrance reaches at least 63 m, and that diving in caves is prohibited. www.dive.is, read 6 Nov
23. Dive.is says a dive averages 7 to 12 m deep, with 18 m as the limit. www.dive.is, read 6 Nov
24. Dive.is says the entrance is about a 100 m walk from the Silfra car park, down a metal staircase to a submerged platform. www.dive.is, read 6 Nov
25. Dive.is dates the opening of the fissure to the earthquakes of 1789. www.dive.is, read 6 Nov
26. Dive.is says meltwater from the Langjökull glacier filters through lava for 30 to 100 years before it reaches Silfra. www.dive.is, read 6 Nov
27. Dive.is says Arctic char visit the fissure, often during the mating season in August and September. www.dive.is, read 6 Nov
28. Dive.is lists an Open Water certification as a minimum for every diver. www.dive.is, read 6 Nov
29. Dive.is sets 17 as the minimum age for divers. www.dive.is, read 6 Nov
30. Dive.is says the Silfra car park is for commercial vehicles, and that visitors park at P5, about a 5-minute walk away. www.dive.is, read 6 Nov
31. Dive.is says the nearest restaurant is at the Thingvellir Information Centre, 3.5 km from Silfra. www.dive.is, read 6 Nov
32. Wikipedia gives a maximum depth of 63 m. en.wikipedia.org, read 6 Nov
33. Wikipedia describes the Cathedral as a fissure 100 m long, with visibility almost from end to end. en.wikipedia.org, read 6 Nov
34. Arctic Adventures says you can see the area on foot, on the park's trails and viewpoints, and stay out of the water. adventures.is, read 6 Nov
35. Arctic Adventures' own website usually gives 30 to 35 minutes of swimming, in a tour of 2.5 to 3 hours on site. adventures.is, read 6 Nov
36. Arctic Adventures gives about 1,000 ISK a day for parking at P5, and about a 5-minute walk from there to the meeting point. adventures.is, read 6 Nov
37. Arctic Adventures says some water through the snorkel is generally harmless, and that there is no need to drink directly from Silfra. adventures.is, read 6 Nov
38. Troll gives a water temperature of about 3 °C and 30 to 45 minutes in the water. troll.is, read 6 Nov
39. Troll warns that the heavy dry suit may make walking difficult, and that you walk short distances in full gear. troll.is, read 6 Nov
40. Troll says the neck and wrist seals must fit snugly, and an extra neck strap may be needed. troll.is, read 6 Nov
41. Troll says your head, hands and part of your face are exposed to the cold water. troll.is, read 6 Nov
42. Troll warns that small leaks can happen at the neck and wrists, and asks you to bring spare thermals. troll.is, read 6 Nov
43. Troll says Silfra has a mild current, and that you must be comfortable swimming against it near the end of the tour. troll.is, read 6 Nov
44. Troll says regular glasses cannot go under the mask, and suggests contact lenses or a prescription mask. troll.is, read 6 Nov
45. Troll says you change outdoors, because the landscape of the park cannot be altered. troll.is, read 6 Nov
46. Troll asks you to arrive in warm socks, thermal leggings and a thermal shirt, and to take off jewellery. troll.is, read 6 Nov
47. Troll advises a hat and gloves, especially in winter. troll.is, read 6 Nov
48. Troll's form rules out pregnancy, heart disease, lung disease, epilepsy, and not being able to walk 1 km. troll.is, read 6 Nov
49. Troll's form asks for a doctor's clearance between 65 and 69, and for blood pressure, some asthma, recent injuries or cancer treatment. troll.is, read 6 Nov
50. Iceland Review reported on 13 February 2017, citing the broadcaster RÚV, that a US visitor lost consciousness on the way back to the bank while snorkeling at Silfra, and was pronounced dead in hospital. www.icelandreview.com, read 5 Nov
51. The police said at the time that it was too early to tell whether this was an accident or a matter of health. www.icelandreview.com, read 5 Nov
52. The same report counts six other serious accidents at Silfra since 2010, three of them fatal. www.icelandreview.com, read 5 Nov
53. Troll's page gives 50 minutes of guided snorkeling in its itinerary. www.getyourguide.com, read 5 Nov
54. Troll's page says at least 145 cm in its text, and rules out people under 135 cm in its list. www.getyourguide.com, read 5 Nov
55. Troll's page sets 69 as the upper age in its text, with a doctor's clearance from 60, and rules out people over 70 in its list. www.getyourguide.com, read 5 Nov
56. Diving Island's page says about 25 to 30 minutes in the water in its text. www.getyourguide.com, read 5 Nov
57. Diving Island's page says it is the only operator at Silfra with dry gloves. www.getyourguide.com, read 5 Nov
58. Diving Island's page says you change indoors, out of the wind. www.getyourguide.com, read 5 Nov
59. Arctic Adventures' page on GetYourGuide gives 45 minutes of snorkeling. www.getyourguide.com, read 5 Nov
60. Arctic Adventures' page advertises up to 150 m of visibility. www.getyourguide.com, read 5 Nov
61. Dive.is' page advertises 100 m of visibility. www.getyourguide.com, read 5 Nov
62. Dive.is' page gives about 45 minutes in the water. www.getyourguide.com, read 5 Nov
63. Dive.is' page says groups are of 6 people, one group per guide. www.getyourguide.com, read 5 Nov
64. Adventure Vikings' page says its wetsuits are 6 mm thick. www.getyourguide.com, read 5 Nov
65. Adventure Vikings' page offers a dry suit or a wetsuit. www.getyourguide.com, read 5 Nov
66. Freedive Iceland's page uses an open-cell 7 mm wetsuit. www.getyourguide.com, read 5 Nov
67. Arctic Adventures' diving page asks for a dry suit certificate, or a logbook with 10 dry suit dives in the last 2 years. www.getyourguide.com, read 5 Nov
68. Arctic Adventures' page says to park at P5, then cross the bridge and walk 400 m along the road. www.getyourguide.com, read 5 Nov
69. Arctic Adventures' page asks you to be in the Silfra car park 15 minutes before your tour. www.getyourguide.com, read 5 Nov
70. Dive.is says cameras check the plates of cars in the parking lots, and that you can pay online or at the Visitor Centre. www.dive.is, read 6 Nov
71. Dive.is warns that road 36 can feel like driving into nowhere, and says to keep going until you see its cars. www.dive.is, read 6 Nov
72. The park charges 1,200 ISK to park a car with six to nine seats. www.thingvellir.is, read 6 Nov
73. The park's conditions name diving, freediving, snorkeling and surface diving. www.thingvellir.is, read 6 Nov
74. Freedive Iceland's page says its van doubles as the changing room. www.getyourguide.com, read 5 Nov
75. Adventure Vikings' page invites you to take a sip of the water. www.getyourguide.com, read 5 Nov