Mass Wasting - Mitigation

Question 1

since when did mgb started hazard assessments

Answer 1

2013 after yolanda

Question 2

hazard assessment under mgb

Answer 2

flood, landslide, ground subsidence/karst, coastal hazard assessments

Question 3

regional and detailed scale maps

Answer 3

1:50000
1:10000

Question 4

they are mandated to conduct studies related to rain-induced landslide

Answer 4

mgb

Question 5

how does mgb conduct geohazard mapping

Answer 5

remote sensing
field assessment
anecdotal accounts

Question 6

what do you look for during field assessment

Answer 6

tension cracks, depth of tension, vertical and horizontal displacement,

Question 7

gently sloping areas with no identified landslides

Answer 7

low landslide susceptibility

Question 8

areas with moderately steep slopes, soil creep and other indications of possible landslide occurrence are present

Answer 8

moderate landslide susceptibility

Question 9

areas with steep to very steep slopes and underlain by weak materials. areas with numerous old/inactive landslides

Answer 9

high landslide susceptibility

Question 10

areas with steep to very steep slopes and underlain by weak materials. recent landslides, escarpments and tension cracks are present. human initiated effects could be an aggravating factor

Answer 10

very high landslide susceptibility

Question 11

areas that could be affected by landslide debris

Answer 11

debris flow/ possible accumulation zone

Question 12

slope classification

Answer 12

0-3 : level to nearly level
3-8 : gently sloping to undulating
8-18 : undulating to rolling
18-30 : rolling to moderately steep
30-50 : steep
>50 : very steep

Question 13

non structural mass wasting mitigation

Answer 13

1. zoning laws
2. construction ordinances
3. geohazard assessment
4. research and extension
5. information dissemination

Question 14

structural mass wasting mitigation

Answer 14

retaining walls
rock bolts
controlling water
terracing
covering steep slopes
reducing slope materials
protective structure

Question 15

if the objective is to prevent movement, then slope stability can be maximized by simultaneously increasing _____ and decreasing _____

Answer 15

frictional forces
the weight acting downslope

Question 16

commonly used whenever a flat or level surface is needed in sloping terrain

Answer 16

retaining walls

Question 17

used to anchor loose rocks to more massive, solid bodies

Answer 17

rock bolts

Question 18

control or limit the amount of water that can accumulate in the slope material

Answer 18

controlling water

Question 19

controlling water involves installment of _____ and ____ which is not common on the Ph

Answer 19

perforated pipes
gravel beds

Question 20

used to cover slope to prevent water from infiltrating

Answer 20

impervious plastic sheet

Question 21

creating a series of benches on a hillside, decreasing steepness but breaks slope into shorter segments

Answer 21

terracing

Question 22

is an ancient practice in parts of asia and south america where they provide flat areas for frowing food

Answer 22

terracing

Question 23

involves covering bare slopes with new vegetation, crushed rocks, or synthetic mesh

Answer 23

covering steep slopes

Question 24

t or f: it may be more expensive to actually remove a dangerous slope rather than try to stabilize it by physical means

Answer 24

FALSE (cost effective)

Question 25

involves building of structures that keep material that is moving downslope from coming into contact with people or surroundngs

Answer 25

protective structures

Question 26

large barriers in valleys to trap debris

Answer 26

trap

Question 27

allow materials to safely move over transportation routes

Answer 27

shelter

Question 28

buildings can be protected by constructing retaining walls that will diver material

Answer 28

diversion

Question 29

how high are the river banks of Davao River?

Answer 29

5m

Question 30

engineering controls are based on the

Answer 30

type off expected movement and the characteristics of the site itself

Question 31

in some cases, landslide engineering control goal is to _______, in other, it is simply to ________

Answer 31

prevent movement ; provide protection from movement

Question 32

used to reinforce both temporary and permanent excavations by spraying concrete

Answer 32

shotcreting

Question 33

________ is important in keeping water from flowing into open fractures at the top of slides and slump

Answer 33

diverting water

Question 34

t or f: the buildup of water in some slopes can be minimized by limiting the amount of water being used nearby for landscape or agricultural irrigation

Answer 34

T

Question 35

terracing is common in

Answer 35

open pit/surface mining or in roadcuts

Question 36

common way of establishing a blanket of grass is a technique called

Answer 36

hydroseeding

Question 37

a slurry of seed and fertilizer is sprayed onto a bare slope

Answer 37

hydroseeding

Question 38

t or f: hydroseeding is costly

Answer 38

T