Áfonya utcai Cave

The Áfonya Street Cave (sometimes written Áfonya utcai-barlang and in many other forms) is a cave located in the Budai Mountains within the Danube–Ipoly National Park, in Budapest District II. It was among the caves specially protected in Hungary.

Description

It is situated on the side of József Hill in Budapest District II, in the garden of the house at 9 Áfonya Street, on a fenced and closed private property, with an entrance sealed by a metal sheet door. The entrance can be reached directly from Áfonya Street. A 22 m long, well‑preserved entrance passage leads into the cave. The cave was formed in the Budai marl during the Eocene by the action of seepage waters breaking through from depth. Spherical chambers, broken and collapsed surfaces, as well as spherical stalactites can be observed inside.

It can be visited with the permission of the Danube–Ipoly National Park Directorate. A maximum of 4 groups may visit per day. A group may consist of up to 4 persons.

In the literature it also occurs under the names Áfonya‑cave (Molnár 1975), Áfonya cave (Németh 1975), Áfonya‑Street‑cave (Cserhalmi 1964), Áfonya‑Street cave (Bertalan 1976), Áfonya Street cavity (Bertalan 1976), Cserhalmi‑cave (Bertalan 1976) and Háztáji‑cave (Leél‑Őssy 1995). In 1983 the cave was first called Áfonya Street cave in the literature.

Research History

In 1963, members of the Customs Guard Cave Research Group, based on a report by László Cserhalmi, entered a cave 25 m into the garden of the house at 9 Áfonya Street after opening the cave entrance. The 1964 Karst and Cave Research Bulletin and the report written by László Cserhalmi state that in early December 1962, due to Cserhalmi’s weight, the ground gave way on one of the garden paths of their house, forming a funnel‑shaped pit with a hole about 1.5 m in diameter at the bottom. Through the hole it could be suspected that a cavity existed. After a 0.5 m deepening, on 2 May 1963 it was possible to enter the cavity. The direction of the entrance corridor is ENE–WSW. Its first task was to build a safe support to avoid further collapse at the entrance.

A reliable lockable door was made for the entrance so that the cave would be safe. The entrance formed where the thickness of the layer between the surface and the cave was the smallest. The cave is located in the upper Oligocene Buda margin. It contains aragonite and hydrothermal spherical chambers. László Cserhalmi removed from the wall a rock fragment on which parallel, 1 cm deep and corroded grooves are present. He made the cave map and, together with a speleological field report, submitted it to the Documentation Committee of the Hungarian Karst and Cave Research Society. He learned that in the immediate vicinity, around 1933, during house construction, several meter‑long cavities were found that contained large spherical chambers. The house was built over them.

Studying the maps of the surrounding caves led to the conclusion that there is a regular repetition of directions in the main fracture orientations. Accordingly, the cave passage should not be far from a fault line at its ENE end. If this is true, then the known part is a side branch, and by breaking through it one can reach the main branch of the cave. Thus a larger‑extent cave can be expected. The cave entrance is 4.2 m east of the house. At the entrance the thickness of the layer between the surface and the cave is 1.5 m, and at the ENE end of the corridor it exceeds 6 m. In the cave the hydrothermal dissolution traces are clearly visible. To a small extent karstification traces are also detectable: about a 2 mm thick stalactite layer on 1 m² of surface. The cave is 28 m long, of which about 19 m of standing length is walkable.

On the levitt organic material (board) about 3–4 months later a 10–12 cm long mold fungus resembling a gray beard grew. On the ash board, near the surface, about a 3 mm red‑stalked and headed fungus grew. The cave has an area of 49.5 m² and a volume of 44.55 m³. The air temperature is 15 °C at 4 m from the entrance, and 17 °C at the farthest point, when the surface temperature was −4 °C. The report includes the cave’s floor‑plan map and longitudinal section map made in 1963. The maps illustrate the cave at a scale of 1 : 200. According to the 1964 news “Karst and Cave See Sunlight”, the measured length of the cave was 28 m, of which 19 m was human‑height. According to the 1975 MKBT report issued about the BSE Nature‑Hiking Department Cave‑Research Group’s 1974 activities, the group would later continue and complete the work started by the group in Áfonya Cave.

The group carried out exploratory work in 1975 in the Áfonya Cave located at 9 Áfonya Street in Budapest's District II. The cave was brought to its attention in 1974 by the Dolphin diving group. The main part of the cave consists of a dome ending in a side dome about 6 m high with a cross‑section of 2–3 m². The marginal layer above the dome is about 4 m thick. Because of the presumed connection with the Molnár János Cave and the large opening near the surface, the group expected the formation to contain abundant series of chambers. At the beginning of the year, due to the danger of the old entrance and to allow easier, faster removal of debris, a shaft was opened above the dome under demolition and then sealed with a door set in a concrete frame. The group's work accelerated, and over about 2.5 m² it lowered the dome's debris level by 2–3 m. The work was greatly hampered by the fact that, as agreed with the residents, the debris could only be accumulated in the courtyard. Here more than 5–6 m³ could not be gathered. With the help of OTVH the debris was managed to be removed once.