Satellite Monitoring of Landside and Rapid Erosion in Southern Luzon: Contributors to Sediment Deposition in the Lingayen Gulf, Northwestern Luzon, Philippines
Salvador, J.H.G.1, Kanbara, H.2, Sato, T.2, Machida, S.3, Hato, M.3, Almeda, R.1,
Gaerlan, S.3, Laserna, S.1 and Apil, F.W. 5
1Mines and Geosciences Boreau, North Ave.,
Diliman, QC, 1101 Philippines.
Fax (632)928-8544
2Nikko Exploration and Development,
Condition., Ltd., 7-10 Toranomon
2-Chrome, Minatoku,Tokyo, Japan.
Fax(81)3-3508-9785
3Earth Remote Sensing Data Analysis Center,
Roppongi First Bldg., Tokyo, Japan
4Mines and Geosciences Bureau,
Regional Office No. 1,
San Fernando, La Union, Philippiness
5Mines and Geosciences Bureau,
Cordillera Administrative Region,
Baguio City, Philippines.
Abstract
Several satellite data such as Landsat MSS, Landsat TM and JERS-1 OPS from 1972 and 1973 covering Northern and Northwestern Luzon, Philippines were studied. Landslide and rapid erosion areas in northern Luzon were interpreted from the images and verified in the field.
The satellite images show that slope failures in northern Luzon have increased in recent years. Sedimentation of river systems also increased. These can be related to the effect of the 1990 Luzon Earthquake. Sediments from these processes eventually find their way into the Lingayen Gulf.
Introduction
The Lingayen Gulf area in northern Luzon is part of the Philippines Northwestern Luzon Growth Quadrangle. The area is characterized by rapid population growth and expansion of urban centers. This growth changes the land cover and puts a strain on the available resources of the area.
At the same time, the area's geoenvironmental condition is changing. The 1990 Luzon earthquake caused slope failures. This couples with strong typhoons hastened the sediment erosion and deposition process. The sediments find their way to the Pangasinan lowlands and eventually into the Lingayen Gulf, both major sources of livelihood in northwestern Luzon. This study aims to monitor the sources of sediments from 1972 to 1994 using Remote Sensing technology. The results will be an input into the region's development plan.
The Agno River is the largest river flowing into the Lingayen Gulf. The total length of the river is about the mountain areas east of Itogon Province characterized by deep valleys and rugged topography. It then flows through the lowlands of Pangasinan before emptying to the Lingayen Gulf in the west.
The vicinity of Itogon Province is considered to be an area where mass movement or the possibility of it occurring is high (DENR and NEDA, 1994).
