NZ Landslides Database Manual

This manual is under development. If you have any questions, comments or suggestions for improvement please email them to ross.roberts@aucklandcouncil.govt.nz.

Please read these instructions before applying for access to the database – access is limited to individuals with the appropriate skills and qualifications.

1.0 Introduction

No single organisation in New Zealand has overall responsibility for landslides. As a result, landslide data has been stored in multiple discrete locations, often in widely varying formats, with no ability to compile the data to get an overall understanding of the distribution of landslide risk across the country.

The New Zealand Landslides Database is designed to enable multiple organisations to deposit factual information about every landslide into a single repository, and for those organisations to be able to access the data for their own purposes.

By sharing this data each organisation will gain significant benefits by understanding how landslides might affect their people and assets. Without this consolidated, consistent and quality assured landslide inventory any efforts to assess spatial landslide hazard or risk will be limited. Landslide hazard assessments are greatly enhanced if they include information on the magnitude, encompassing the distribution, type, density, size and impacts of landslides, and temporal frequency of past landslide events.

2.0 Before you start

2.1 Getting access to edit

To help ensure that the data entered is robust and reliable, only suitably qualified and experienced people will be given edit access. In general the level of knowledge and skill needed is that of an Engineering New Zealand Professional Engineering Geologist (PEngGeol) or equivalent. Users are expected to have a robust understanding of landslide classification schema, and to understand the importance of reliable quality data management.

A fully-functional QA system is being developed for the database. In the interim, a limited QA process is in place (see section 6) and access will be strictly limited and peer-review will be required to maintain data quality.

To be granted access to the database, please enter your details in this form: https://forms.office.com/r/VFN9kdJVgy

2.2 Getting access to view

There is no log-in for view only access. However, the data can be viewed through external GIS systems in our partner agencies through an API. Please contact Ross Roberts to request access, or LandslideSupport@beca.com for technical details.

2.2 Getting support

For support, please contact LandslideSupport@beca.com

3.0 Getting started

Access the database here: https://app.facilitytwin.com/

The quick-start guide explains the basics of login, navigation and data entry:

4.0 Database design

4.1 Design philosophy

Understanding the reasoning behind the database design will help the user with data entry. The basics are described below:

  • Each landslide is unique – it has a unique identifier that never changes.
  • Only factual data is stored. To avoid issues with confidentiality, the database only stores information about the physical attributes and publicly available consequences. Private data (such as insurance claim details, landowner contact details etc) are expected to be stored in separate databases within the relevant organisations, which should be linked to the unique landslide ID to maintain data integrity and privacy.
  • Each landslide can have a parent – a small landslide may be part of a larger feature. These links can be added at any time, as new information becomes available.
  • Minimal data is required to create a record. When a landslide is first reported, little may be known about it. The database is structured to allow data to be added over time.
  • Landslides change. As new data is added, each change is recorded. A time-slider allows change over time to be reviewed. This includes spatial mapping, which can be edited and added to over time, and these changes will all be tracked.
  • Quality assurance is essential. The history tracking described above allows a clear, documented trail of all changes (change log), records who made each change and the reason for the change (e.g. the change may be that new information became available, or the landslide reactivated and physically changed, or to correct an older error in the data).
  • Data is not duplicated. Where data is more appropriately entered into a different database, it’s referenced instead (e.g. boreholes should be entered into the NZ Geotechnical Database and cross-referenced).
  • Where possible, data entry is limited to drop-down options aligned with the Hungr (2014) update to the Varnes classification scheme.

4.2 Structure

The database comprises two individual elements:

  • A public reporting tool, to allow anyone to submit key information about landslides for review. This is a simple form designed for use by anyone to collect the basic information required for decision-making by experts.
  • The main database, containing detailed information about each landslide. This is accessible only to registered users, with the intent being that these are limited to Professional Engineering Geologists (PEngGeol) or others with similar levels of understanding about landslides.

Each landslide commences with a master record, which is given a unique ID and is associated with a single point on a map. All the core landslide schema data is recorded against this location.

All the more detailed features (such as polygons showing the landslide area) are linked to this master record.

 

Fig 1 – Overview of the basic database structure.

The core data about each landslide is stored in the master metadata table, which creates one source of truth for the landslide. A complex landslide may require details to be recorded for each smaller landslide within the main feature (for example, where each landslide has a different style or rate of movement). This is achieved by creating each sub-landslide as an individual record, creating the over-arching landslide as an individual record, and linking all the sub-landslides to the over-arching landslide as their ‘parent’.

In addition to the core metadata, an unlimited number of spatial features can be assigned to each landslide. These are entered graphically, and are summarised in the table below. More details are presented below.

Feature classTypesTypical content
Landslide featuresPoints
Lines
Polygons
Landslide area, source area, debris area, hummocky ground, sinkholes, springs, scarp lines, cracks, damaged structures, breaks of slope, streams, landslide dammed lakes, etc.
Corrective featuresPoints
Lines
Polygons
Drains, retaining walls
PhotographsPointsImages
InvestigationsPointsLinks to NZ Geotechnical Database
Table 1 – Summary of spatial features that can be attached to each landslide

Each landslide can also have unlimited attachments. These can include pdf reports, photographs, spreadsheets of monitoring data, maps, URLs to link to external websites, etc.

5.0 Core metadata

In the main data entry page, the metadata is collected into groups of related information to simplify the data entry. These can be entered in any order, and will be ‘lodged’ into the database and sent for QA review when the Submit button is pressed. This button does not need to be pressed after every page, or after every field, and no data will be lost if you exit the database without pressing this button.

Fig 2 – Main metadata entry page

The core metadata is as follows:

GroupData fields
1. Identifiers1.1 Parent landslide
1.2 Landslide name
2. Location2.1 Location description
2.2 Location recording method or device
2.3 Estimated error in location recording method
3. Description and setting3.1 Physical setting
3.2 Geological Setting
3.3 Geomorphological Setting
3.4 Landslide Description
4. Movement4.1 Primary movement type
4.2 Primary movement type subclass
4.3 Secondary movement type(s)
4.4 Complexity of mass movement
5. Date and activity5.1 Has the landslide been active in the last 1000 years?
5.2 Landslide activity
5.3 Velocity class / rate of movement
5.4 Date of first movement
5.5 Accuracy of dating method
6. Shape and dimensions6.1 Slope angle prior to landslide
6.2 Slope angle of displaced material
6.3 Angle of rupture surface (translational)
6.4 Aspect (direction of movement)
6.5 Length along ground zone of depletion
6.6 Length along ground zone of accumulation
6.7 Maximum height of main scarp
6.8 Maximum width of landslide perpendicular to direction of movement
6.9 Maximum depth from original surface to surface of rupture
6.10 Travel angle
6.11 Estimate of landslide area (min)
6.12 Estimate of landslide area (max)
6.13 Estimate of landslide volume (min)
6.14 Estimate of landslide volume (max)
6.15 Volume/area estimation method
7. Materials7.1 Materials in landslide
7.2 Debris type
7.3 Vegetation cover
8. Triggers8.1 Primary causal triggering factor
8.2 Other factors influencing instability
8.3 Estimated magnitude of earthquake causing landslide
8.4 Rainfall total in preceding 24 hours
8.5 Rainfall total in preceding 3 days
8.6 Rainfall total in preceding 7 days
9. Consequences9.1 Damage description
9.2 Approximate number of injured people
9.3 Approximate number of fatalities
9.4 Approximate damage cost
9.5 Environmental damage
9.6 Features and assets impacted by the landslide
10. Legacy data links10.1 GNS – Number of Slips
10.2 GNS – Size Category
10.3 GNS – Injuries
10.4 GNS – Deaths
11. Information sources11.1 Source of landslide information (description)
11.2 Source bibliography
11.3 Project name / number
11.4 Original database (for bulk uploaded files)
12. Quality assurance12.1 Reported by (Name)
12.2 Reported by (email)
12.3 QA Name
12.4 QA Person email
12.5 QA level
12.6 QA status
12.7 Comments
Table 2 – Basic field structure

Each of these data fields has specific guidelines on what can be entered:

5.1 Identifiers Group

FieldDrop-down options (where relevant)Expected formatGuidance
1.1 Parent landslideLook-up of existing landslidesChoiceWhere the landslide being entered is a sub-feature of a larger area of mass movement, select the parent landslide here to create a link between the two features. A thorough search should be done before a parent is assigned. There should be a ‘genetic’ link or obvious spatial enclosure for a landslide feature to have a parent.
1.2 Landslide nameTextCommon name for landslide feature. Historical published names should be favoured (e.g., ‘Casuarina Crescent’or ‘Grooms Slip’) and this may also include the year (e.g., ‘Beauty Point 1952 Landslide’).
Table 3.1 – details of group 1

5.2 Location Group

FieldDrop-down options (where relevant)Expected formatGuidance
2.1 Location descriptionTextCommon name for landslide feature. Historical published names should be favoured (e.g., ‘Casuarina Crescent’or ‘Grooms Slip’) and this may also include the year (e.g., ‘Beauty Point 1952 Landslide’).
2.2 Location recording method or deviceTextDescribe the method used for identifying the location (e.g. hand-held GPS, aerial photographs etc).
2.3 Estimated error in location recording method<1m
<10m
<100m
<1km
<2.5km
<25km
Choice
Table 3.2 – details of group 2

5.3 Description and setting group

FieldDrop-down options (where relevant)Expected formatGuidance
3.1 Physical settingCoastal cliff
Cutting (e.g. road, railway, quarry)
Inland cliff
Man-made fill
Natural slope
Other
Choice
3.2 Geological SettingTextText summary of the geological setting including general structural history and lithological types if known. Should be concise, e.g., ‘Brecciated fault contact between sandstone and mudstone’.
3.3 Geomorphological SettingTextText summary of the geomorphological setting including landforms, slope, aspect, interpreted Tertiary and/or Quaternary environmental settings and related processes. Should be concise e.g., ‘Steep NE facing slope on old volcanic centre, deep weathering profile’.
3.4 Landslide DescriptionTextGeneral description of the landslide
Table 3.3 – details of group 3

5.4 Movement group

FieldDrop-down options (where relevant)Expected formatGuidance
4.1 Primary movement typeErosion
Fall
Flow
Retaining wall failure
Slide
Slope deformation
Spread
Topple
Other
Not collected
Unknown
ChoiceAs defined in Hungr 2014 (with additions)
4.2 Primary movement type subclassChanges depending on choice in 4.1ChoiceAs defined in Hungr 2014 (with additions)
4.3 Secondary movement type(s)Same as 4.1As defined in Hungr 2014 (with additions)
4.4 Complexity of mass movementMultiple events, multiple styles (composite)
Multiple events, one style (multiple/successive)
One event, multiple styles (complex)
One event, one style (single)
Choice
Table 3.4 – details of group 4



5.5 Date and activity group

FieldDrop-down options (where relevant)Expected formatGuidance
5.1 Has the landslide been active in the last 1000 years?Certainly
Probably
Probably not
No
Unknown
ChoiceAllows filtering out of inactive landslides
5.2 Landslide activityActive
Reactivated
Suspended
Inactive – Dormant
Inactive – Abandoned
Inactive – Stabilised
Inactive – Relict
Unknown
Choice
5.3 Velocity class / rate of movementExtremely rapid
Very rapid
Rapid
Moderate
Slow
Very Slow
Extremely slow
Unknown
ChoiceDate that the landslide first occurred. If not known accurately, give a best estimate and clarify in the ‘accuracy of dating method’ field.

If no indication is know, set date to 1 Jan 1000
5.4 Date of first movementDate/timeUse this to give an indication of how reliable the date of first movement is.
5.5 Accuracy of dating methodSecond
Minute
Hour
Day
Month
Year
Decade
Century
Unknown
Not recorded
Choice
Table 3.5 – details of group 5



5.6 Shape and dimensions group

FieldDrop-down options (where relevant)Expected formatGuidance
6.1 Slope angle prior to landslideNumberAs defined in figures 3.3, 3.4, 3.5, and 3.7 of Cruden & Varnes
6.2 Slope angle of displaced materialNumberAs defined in figures 3.3, 3.4, 3.5, and 3.7 of Cruden & Varnes
6.3 Angle of rupture surface (translational)NumberAs defined in figures 3.3, 3.4, 3.5, and 3.7 of Cruden & Varnes
6.4 Aspect (direction of movement)North
North-East
East
South-East
South
South-West
West
North-West
Unknown
Choice
6.5 Length along ground zone of depletionNumber
6.6 Length along ground zone of accumulationNumber
6.7 Maximum height of main scarpNumber
6.8 Maximum width of landslide perpendicular to direction of movementNumber
6.9 Maximum depth from original surface to surface of ruptureNumber
6.10 Travel angleNumber
6.11 Estimate of landslide area (min)Number
6.12 Estimate of landslide area (max)Number
6.13 Estimate of landslide volume (min)Number
6.14 Estimate of landslide volume (max)Number
6.15 Volume/area estimation methodTextDescribe how the volume was estimated and comment on likely accuracy
Table 3.6 – details of group 6



5.7 Materials group

FieldDrop-down options (where relevant)Expected formatGuidance
7.1 Materials in landslideRock
Soil
Ice
Boulders
Cobbles
Gravel
Sand
Silt
Clay
Other
Unknown
Not collected
Choice
7.2 Debris typeBlocky
Chaotic
Unknown
Other
Not collected
Choice
7.3 Vegetation coverUnknown
Not collected
None
Pasture
Soil con plantings
Scrub
Indigenous forest
Choice
Table 3.7 – details of group 7



5.8 Triggers group

FieldDrop-down options (where relevant)Expected formatGuidance
8.1 Primary causal triggering factorEarthquake
Rainfall
Tectonic / volcanic uplift
Erosion / scour / piping
Devegetation
Melting snow/ice
Weathering / material degradation
Excavation
Structure failure
Broken pipes
Drawdown of reservoir
Groundwater change
Mining
Artificial vibration
Stress change
Other
Unknown
Not collected
ChoiceSelect the primary causal triggering factor. Where the primary cause isn’t known, choose ‘unknown’ and put the likely triggers into the ‘other factors causing instability’ field.
8.2 Other factors influencing instabilityAs per 8.1Multichoice
8.3 Estimated magnitude of earthquake causing landslideNumber
8.4 Rainfall total in preceding 24 hoursNumber
8.5 Rainfall total in preceding 3 daysNumber
8.6 Rainfall total in preceding 7 daysNumber
Table 3.8 – details of group 8



5.9 Consequences group

FieldDrop-down options (where relevant)Expected formatGuidance
9.1 Damage descriptionText
9.2 Approximate number of injured peopleNumber
9.3 Approximate number of fatalitiesNumber
9.4 Approximate damage costNumber
9.5 Environmental damageText
9.6 Features and assets impacted by the landslidePrivate house (building, not including gardens)
Public or commercial building
Private driveway or garden
Public road
Public walkway or path
Railway
Pipes, powerlines or other infrastructure
Retaining wall or sea wall
Public land
Other
Multichoice
Table 3.9 – details of group 9



5.10 Legacy data linkages to GNS database group

These fields allow the import of data from the existing GNS landslides database without over-writing the equivalent fields with different data entry options in the new database. For example, in the new database the number of deaths is an actual number, not a choice range.

FieldDrop-down options (where relevant)Expected formatGuidance
10.1 GNS – Number of SlipsNone
Many
Several
Not collected
Unknown
Choice
10.2 GNS – Size CategoryLarge
Moderate
Small
Not collected
Unknown
Choice
10.3 GNS – InjuriesNone
Many
Several
Not collected
Unknown
Choice
10.4 GNS – DeathsNone
Many
Several
Not collected
Unknown
Choice
Table 3.10 – details of group 10



5.11 Information sources group

FieldDrop-down options (where relevant)Expected formatGuidance
11.1 Source of landslide information (description)Text
11.2 Source bibliographyText
11.3 Project name / numberText
11.4 Original database (for bulk uploaded files)Text
Table 3.11 – details of group 11



5.12 Quality assurance group

FieldDrop-down options (where relevant)Expected formatGuidance
12.1 Reported by (Name)Text
12.2 Reported by (email)Text
12.3 QA NameTextThe name of the person who has undertaken QA checking of the most recent submission.
12.4 QA Person emailTextThe email address of the person who has undertaken QA checking of the most recent submission.
12.5 QA level(A) Complete and Correct
(B) Complete
(C) Incomplete – data entered.
(D) Unknown
Choice(A) Complete and Correct – only assigned after check of data entry and field verification of the data by an engineering geologist.
(B) Complete – all data easily available entered, further QA may be required.
(C) Incomplete – some data missing.
(D) Unknown – unknown level of QA on historical data.
Add notes in the comments section explaining your decision.
12.6 QA statusOpen
Problem
Closed
ChoiceOpen (fit for publication), Problem (an issue has been identified, but can remain published while being assessed), Closed (not fit for publication due to outdated, unreliable, or incomplete data).
Add notes in the comments section explaining your decision.
12.7 CommentsTextFree field to comment on QA issues
Table 3.12 – details of group 12

6.0 Spatial features

The database is intentionally structured to allow data entry with only a location, as the spatial extent and other physical details are often not collected when the landslide is first identified. These features can be added later (through the web mapping interface) as the information is collected, and can be edited over time as the landslide changes or as new data is obtained.

The history records all changes to the spatial features, and the time-slider can be used to visualise change over time.

6.1 Overview

Features that can be sketched for each landslide are:

PointsLinesPolygons
MorphologyCrown
Concave break of slope
Ground cracking
Convex break of slope
Eroded gully
Flank
Scarp
Landslide area
Gully erosion
Source area
Debris area
Hummocky ground
StructuresDamaged structureDamaged structureDamaged structure
WaterSinkhole
Spring/seepage
StreamLandslide dammed lake
Pond or lake
Corrective actionCorrective action featureCorrective action featureCorrective action feature
PhotoPhoto
Ground investigationInvestigation point
OtherOther
Unknown
Other
Unknown
Other
Unknown
Table 4 – summary of spatial features available

For each of these spatial features, there is a small metadata set to allow useful description.

6.2 Morphology, structures & water (polygons)

FieldDrop-down options (where relevant)Expected formatGuidance
TypeLandslide area
Gully erosion
Source area
Debris area
Hummocky ground
Damaged structure
Landslide dammed lake
Pond or lake
Other
Unknown
Choice
DescriptionTextFree field for description
Table 5.1 – details of GIS features metadata (morphology, structure & water polygons)

6.3 Morphology, structures & water (lines)

FieldDrop-down options (where relevant)Expected formatGuidance
TypeCrown
Concave break of slope
Ground cracking
Convex break of slope
Eroded gully
Flank
Scarp
Damaged structure
Stream
Other
Unknown
Choice
DescriptionTextFree field for description
Table 5.2 – details of GIS features metadata (morphology, structure & water lines)

6.4 Morphology, structures & water (points)

FieldDrop-down options (where relevant)Expected formatGuidance
TypeDamaged structure
Sinkhole
Spring/seepage
Other
Unknown
Choice
DescriptionTextFree field for description
Table 5.3 – details of GIS features metadata (morphology, structure & water points)

6.5 Corrective action feature (polygon)

FieldDrop-down options (where relevant)Expected formatGuidance
TypeGround improvement
Toe weight
Crest excavation
Soil redistribution
Surface treatment
Mesh
Soil nails
Dewatering zone
Planting
Other
Unknown
Choice
DescriptionTextFree field for description
IntegrityFully functional
Partly functional
Failed
Decommissioned (replaced)
Decommissioned (not replaced)
Other
Unknown
Choice
DateDate/timeThe date the corrective measure was put in place (not the date the entry was made in the database – this is automatically captured)
Table 5.4 – details of GIS features metadata (corrective action feature polygons)

6.6 Corrective action feature (line)

FieldDrop-down options (where relevant)Expected formatGuidance
TypeRetaining wall
Gabions / mass
Line of anchors
Catch barrier / dam
Guide barrier / dam
Drainage – pipe
Drainage – counterfort
Drainage – other
Other
Unknown
Choice
DescriptionTextFree field for description
IntegrityFully functional
Partly functional
Failed
Decommissioned (replaced)
Decommissioned (not replaced)
Other
Unknown
Choice
DateDate/timeThe date the corrective measure was put in place (not the date the entry was made in the database – this is automatically captured)
Table 5.5 – details of GIS features metadata (corrective action feature lines)

6.7 Corrective action feature (point)

FieldDrop-down options (where relevant)Expected formatGuidance
TypePile
Anchor
Drainage – manhole
Drainage – exit point
Other
Unknown
Choice
DescriptionTextFree field for description
IntegrityFully functional
Partly functional
Failed
Decommissioned (replaced)
Decommissioned (not replaced)
Other
Unknown
Choice
DateDate/timeThe date the corrective measure was put in place (not the date the entry was made in the database – this is automatically captured)
Table 5.6 – details of GIS features metadata (corrective action feature points)

6.8 Photo point

FieldDrop-down options (where relevant)Expected formatGuidance
TypeOverview
Detail
Sketch
ChoiceAllows sketches as well as photographs to be georeferenced
OrientationDegreesDescribes the direction in which the photo was taken relative to north.
DateDate/timeThe date and time the photo was taken
Table 5.7 – details of GIS features metadata (photo points)

6.9 Investigation point

FieldDrop-down options (where relevant)Expected formatGuidance
Investigation point typeInclinometer
Piezometer
Borehole
Extensometer
Survey point
Other
Unknown
Choice
Feature IDNumberUnique ID from New Zealand Geotechnical Database to allow cross-referencing
Table 5.8 – details of GIS features metadata (Investigation points)

7.0 Quality assurance

The primary control on quality assurance is limiting access to suitably qualified and experienced individuals. In addition, there is a QA process built into the database. The process is as follows:

  1. The landslide data is entered by a suitably qualified and experienced person. They do not fill in fields 12.3 to 12.7 (in the QA section), and do not tick the “Is this landslide valid?” box. Once they have entered all available data, they press the “submit” button. At this stage the landslide appears in the “Validate Landslides” table – but is not shown on the main map.
  2. The nominated QA person from the same organisation as the data entry person (or external if no suitable individual) opens the landslide from the “Validate Landslides” table and checks all data against their records
  3. If the nominated QA person is satisfied that the data is correct, they:
    • Set the QA Level to “A – complete and correct”
    • Set the QA Status to “Open”
    • Tick the check-box labelled “Is this landslide valid?” – this makes the landslide visible to other users on the main map

The date, time, and user name of the individual making these changes is recorded in the change log as part of the QA process.

Fig 3 – sample history in the change log showing who made each change, when the change was made, and what fields were changed

If more changes are made to the landslide after the QA process is completed, these will show in the QA log. It is expected that the QA person will then re-check the data and reconfirm the validity. This is not yet built-in to the system as an automated process, so it is expected that good communication will be required.