TRENGGALEK – Authorities are conducting a detailed assessment of the Trenggalek-Ponorogo landslide at KM 16 on the national road linking Trenggalek Regency and Ponorogo Regency, as officials move beyond emergency cleanup and focus on preventing another collapse.

The landslide recently blocked part of the route, prompting crews to clear debris and reopen access. Now, engineers from the East Java-Bali National Road Implementation Center (BBPJN) are studying the soil and rock structure around the slope to understand what triggered the incident.

Technical teams have started a topographic survey near the hillside in Nglinggis Village. The survey focuses on the upper section of the slope, which officials believe may be the main source of the landslide.

“We are surveying the upper part of the slope to identify what causes the soil movement,” said Endhy Aktony.

Engineers are examining several possible factors. Water flow, nearby farmland, and unstable soil layers could all contribute to the slope’s movement.

“We must understand the soil structure in detail before deciding on permanent repairs,” Aktony said. “Fixing the lower section will not help if material continues sliding from the hilltop.”

Early inspections show that the retaining wall at the base of the slope remains relatively stable. Large rocks from the landslide cracked the outer part of the structure, but the main foundation remains intact.

While engineers continue their analysis, authorities are also working to restore the road ahead of the Eid homecoming travel season, when traffic typically rises across regional routes.

Construction crews have begun preparing several temporary measures. Workers plan to level the road surface using Class A base material to stabilize the affected section.

They will also install tarpaulins along the lower slope to prevent rainwater from soaking into the soil. Excess moisture can weaken the ground and increase the risk of further movement.

In addition, crews are preparing a temporary asphalt layer, known as blacktop, to ensure vehicles can pass safely through the area while longer-term repairs are planned.

Joint teams from several government agencies continue monitoring conditions at KM 16. Officials hope the technical study will help identify a permanent solution to reduce landslide risks along the Trenggalek-Ponorogo corridor.

“Our target is to complete the temporary blacktop before Eid,” Aktony said. “We also installed tarpaulins to reduce rainwater infiltration and keep the soil stable.”

Authorities say the road remains an important transportation link for communities and economic activity between the two regions.