Skip to Content


Mass Wasting on Highway 33

Hidden : 5/19/2009
3 out of 5
1 out of 5

Size: Size: not chosen (not chosen)

Join now to view geocache location details. It's free!


How Geocaching Works

Please note Use of services is subject to the terms and conditions in our disclaimer.

Geocache Description:

Mass wasting has many forms. At this location there is one clear example of mass wasting. What kind of mass wasting is it? Can you figure out what happened here?

This location can be viewed from a large pullout on the west side of Highway 33.

The relatively steep sides of the valley are composed of Matilija Sandstone. The Matilija Sandstone was deposited in the Eocene (46 to 48.5 million years ago) in a marine environment. This coarse grained formation is a series of deep-ocean turbidites (see Point Mugu Turbidites) that likely formed off a tectonically active coast that creates steep mountains near the shore along with steep off-shore ocean bottoms.

Even though this rock formation is quite strong, it is still affected by mass wasting. Mass wasting is the movement of soil and rock under the influence of gravity. Gravity by nature pulls material down hill. While there are many ways to classify mass wasting, they are often categorized into one of the following categories

  • Creep - slow, nearly continuous downslope movement;
  • Slides - sudden downhill movement;
  • Flows- dense, fluid mixtures;
  • Falls – airborne or nearly airborne movement.

Mass wasting events may have characteristics of each of these categories, but they are named based on the predominant form of movement. Other terms are sometimes used to describe gradations between the categories above. A mass wasting event is further categorized into broad groups that give the impression of the type or size of material in motion. For example:

  • Rock – any particle larger than a pebble
  • Land/Earth – particles smaller than a pebble
  • Mud – small particles with a significant component of water
  • Debris – a mixture of soil, vegetation, and other material

Putting these two elements together creates the matrix for naming mass wasting events:







Rock Creep

Rock Slide


Rock Fall



Land Slide

Earth Flow




Mud Slide

Mud Flow




Debris Slide

Debris Flow

Debris Fall

Not all of these combinations are used and other combinations that more accurately describe an event can be created. Additionally, some combinations don’t normally occur since the material involved would not create a slope required for that type of mass wasting event. For example, mud would not be found on a vertical slope required for a fall so a mud fall would not be found. In other cases, such as creep, the type of material is often not included.

Logging requirements:
Send me a note with :

  1. The text "GC1RHZP Mass Wasting on Highway 33" on the first line
  2. The number of people in your group.
  3. Using the naming methodology above classify the mass wasting event that occurred on the mountain side to across HWY 33 to the north. Note: there is absolutely no need to cross the highway.

Find more Earthcaches

Additional Hints (No hints available.)



90 Logged Visits

Found it 86     Write note 3     Publish Listing 1     

View Logbook | View the Image Gallery

**Warning! Spoilers may be included in the descriptions or links.

Current Time:
Last Updated:
Rendered From:Unknown
Coordinates are in the WGS84 datum

Return to the Top of the Page

Reviewer notes

Use this space to describe your geocache location, container, and how it's hidden to your reviewer. If you've made changes, tell the reviewer what changes you made. The more they know, the easier it is for them to publish your geocache. This note will not be visible to the public when your geocache is published.