The landforms of Jalajala are grouped into three (3)
major physiological land units, namely: collu-alluvial forms, footslopes, and
The minor alluvial plain is
a fan-shaped alluvial plain that is formed when rivers and streams leave behind
some sediments from mountains and hills into the lowland. These consist of
clay, silt, sand, gravel and cobbles. This formation produces a moderate to
very deep soil and is planted mostly to palay and in some places, vegetables
and fruit trees. Shrubs and grasses also cover a large portion of this
landform. This landform covers about 1,776.04 hectares or 36.03% of the land
The footslopes or piedmont
covers an area of 362.84 hectares or 7.36% of the municipal land area. These
are gently sloping lands formed by gradual deposition of materials at the foot
of a hill or mountain. The soils of this form are derived from volcanic
materials, underlined weathered rock fragments that are course loamy to clay.
This landform is also usually planted to paddy rice and fruit trees.
The hills are sub-divided into two (2) classes: the
andesitic hills with high relief and the volcanic agglomerate hills with low
relief covering an area of 2,112.84 hectares or 42.86% and 481.24 hectares or
9.76% of municipal total, respectively.
Generally sharp crested ridges due to the rock’s
relative susceptibility to weathering and erosion characterize the andesitic
hill landform. The rock that forms these
hills are medium to fine in texture and greenish gray to gray in coloration.
The mineral assemblage consists of biotite, hornblende and feldspar with minor
quartz. The volcanic agglomerate hills,
on the other hand, are formed by the accumulation of volcanic aggregates of
angular to sub-rounded fragments of andesite, with the latter predominating,
and cemented in a tuffaceous matrix of the same composition. Some of the fragments are observed to exhibit
twisted forms indicating that they were ejected in a liquid state. Also, they
are often vesicular particularly in their outer layer.
The miscellaneous landform
includes creek escarpment, quarry and lake. It also includes the urban or built-up
areas, which for Jalajala covers 197.04 hectares or 4.00% of municipal total.