Salt Mud Slide

Coordinates: 45°54′47″N 13°51′55″E / 45.91306°N 13.86528°E The Salt Mud Slide (Slovene: plaz Slano Blato) is a periodic landslide in Slovenia that is triggered approximately once a century.[1]

The landslide is located below Mount Čaven and Little Mountain (Slovene: Mala gora) next to the Platna mountain pasture.[2] It is moving along Grajšček Creek (which also originates in the landslide itself[3]) toward the settlement of Lokavec near Ajdovščina.[1] It is 1,010 to 1,300 m long and 60 to 250 m wide, covering approximately 15 ha between the elevations of 360 and 660 m.[1][4] Its maximum flow rate was recorded at 100 m/day.[1]

Although around 8,000 active landslides are present in Slovenia, the Salt Mud Slide stands out as one of the most serious in terms of the damage it has caused.[5]:103

Name

The name of landslide area was recorded as Blatna ('muddy') in 1881.[1] The origin of the designation 'salt(y)' (Slovene slan) is uncertain. A local folk belief states that the high cleanup cost of the landslide resulted in an exorbitant cost (cf. Slovene zasoliti 'to over-salt'; metaphorically, 'to charge excessively'). However, the landslide bore the designation 'salt(y)' before any cleanup efforts were ever made.[1][6]

Other locals state that sheep used to wander down to the area from nearby pastures, where they would lick the mud as a natural salt lick. This basis for the name's origin is supported by the fact that chemical analysis of the water at the landslide has shown it to have a very high mineral content, including sodium sulfate, also known as Glauber's salt.[1][7]

History and activity

Oral tradition regarding the landslide goes back four centuries, connecting it to the construction of a small church dedicated to Saint Urban on the slope of Mount Čaven above Lokavec and below the landslide. Saint Urban was invoked as a protector against natural disasters, and particularly with regard to a lake that people believed was hidden inside Mount Čaven that threatened to flood the valley.[7][8]

A 1789 source by Belsazar Hacquet mentioned the landslide, describing its debris flow in 1786.[7] It was described again in an 1887 report[9] that discussed the landslide event of 20 October 1885, in which 30 m of the road from Ajdovščina to Gorizia was destroyed.[7] Cleanup efforts and landslide mitigation measures were carried out by Austrian authorities in 1903.[1][10]

In November 2000, heavy rain and warm weather triggered the Salt Mud Slide, which buried about 15 hectares of grassland and forest.[1] A secondary flow was triggered in September 2001.[7] The landslide stopped moving after this and is currently considered stable.[5]:102 Following these events, an access road was built and 230,000 m³ of material was removed from the lower part of the landslide and deposited north of the Ajdovščina Airport.[7]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Kovač, Mirko, & Marko Kočevar. 2001. Plaz Slano Blato nad Lokavcem pri Ajdovščini. UJMA 14–15: 122–129. (with photos, maps) (Slovene)
  2. ↑ Platna Pasture at Geopedia
  3. ↑ Savnik, Roman, ed. 1968. Krajevni leksikon Slovenije, vol. 1. Ljubljana: Državna založba Slovenije. p. 24.
  4. ↑ Zorn, Matija, Blaž Komac, Milan Orožen Adamič, & Karel Natek. 2008. Zemeljski plazovi v Sloveniji. Ljubljana: Založba ZRC, p. 39.
  5. ↑ 5.0 5.1 Komac, Blaž & Matija Zorn. Pobočni procesi in človek. Ljubljana: Založba ZRC.
  6. ↑ Rosana Rijavec. 2009. "Plaz Slano blato kljub sanaciji ne miruje". Večer (30 January).
  7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 Benko, Igor. 2011. Zgodovinski pregled intervencij na plazu Slano blato. Paper presented at the conference Šukljetovi dnevi, Ajdovščina, 30 September 2011. (with photos, map) (Slovene)
  8. ↑ Slokar, Boris. "Sprehod do sv. Urbana" (with photos, map) (Slovene)
  9. ↑ Fifer Bizjak, Karmen, & Andreja Zupančič-Valant. 2007. Rheological investigation for the landslide Slano Blato near Ajdovščina (Slovenia). Geologija 50: 121–129, p. 121.
  10. ↑ Medvešček, Peter. 1904. Opis Sv. Križa. Gorica.

External links

Platna Pasture at Geopedia, showing the adjacent (unlabeled) Salt Mud Slide