Prediksi Daerah Rawan Longsor Pada Kawasan Pengembangan Jalan Nasional Pulau Sanana di Maluku Utara

Research has been conducted with the aim of mapping a potential landslide of soil that is alleged to be happening on a national road development area on the island of North Maluku Sanana island because in some locations excavations or cutting slope were conducted for build trails. Research was done by survey method, by analysis of land as well as the analysis of soil samples in the laboratory against some physical-chemical soil parameters to predict the potential for landslide of soil. The results showed that in the developed area of national roads, there were some points or locations with the potential landslide. However, by cutting slope of landslide the potential became greater, things which would be very threatening road users on the sections of the road that passes through the hilly and mountainous regions. The cutting slopes have been disturbing the equilibrium slope stability or lower slopes so the landslide is easy to happen. Mitigation efforts can be done by building a retaining structure at the foot of the slopes, the angle of the cutting slope made slightly sloping and in the upper part land use should be preserved and enriched with plant conservation to improve the stability of slopes. Keywords: a potential avalanche of soil, national road, slope stability   ABSTRAK Penelitian telah dilakukan dengan tujuan untuk memetakan potensi longsoran tanah yang diduga akan terjadi pada kawasan pengembangan jalan nasional di Pulau Sanana Maluku Utara karena di beberapa lokasi dilakukan penggalian atau pemotongan lereng untuk membangun jalur jalan. Penelitian dilakukan dengan metode survey dengan analisis lahan serta analisis sampel tanah di laboratorium terhadap beberapa parameter fisik-kimia tanah untuk memprediksi potensi longsoran tanah. Hasil penelitian menunjukkan bahwa pada kawasan ruas jalan nasional yang dikembangkan terdapat beberapa titik atau lokasi dengan potensi longsoran tergolong sedang. Namun dengan adanya pemotongan lereng maka potensi longsoran menjadi semakin besar, hal mana akan sangat mengancam pengguna jalan di ruas-ruas jalan yang melewati kawasan berbukit dan bergunung. Pemotongan lereng telah mengganggu keseimbangan lereng atau menurunkan stabilitas lereng sehingga longsoran mudah terjadi. Upaya mitigasi dapat dilakukan dengan membangun struktur penahan di kaki lereng, sudut pemotongan lereng dibuat landai dan penggunaan lahan di bagian atas lereng harus dipertahankan dan diperkayadengan tanaman konservasi untuk meningkatkan stabilitas lereng yang sudah terganggu. Kata kunci: jalan nasional, potensi longsoran tanah, stabilitas lereng