While walking on the campus beach down from Lagoon Road, Martie Levy said she heard a rumbling noise originating 25 feet behind her and her daughter — just before a four-foot-wide boulder rolled down from the cliff.

It was a Sunday afternoon this past April when a middle section of the bluff broke apart, said Levy, who is UCSB’s director of Capital Development in the Office of Budget and Planning. An overhang of grass and plants protruded from where the boulder had fallen.

Like the Isla Vista bluffs along Del Playa Drive, the campus cliffs are eroding at what several university officials and professors consider an alarming rate. County officials evicted residents from several oceanside properties due to the erosion danger, and some houses have already been demolished with plans for relocation further back from the bluffs’ edge. Likewise, some professors have forecasted that erosion may threaten key university access points and buildings within the next 50 years if no action is taken against it. As of yet, no one has come forth with a plan to stem the erosion, or a way to provide safety and adequate beach access along the gradually retreating university cliffs.

About three days after the April landslide witnessed by Levy, geology professor emeritus Arthur Sylvester said he investigated the site and found that more debris – including the grass overhang — had cascaded down to the cliff’s base. He said the amount of rubble could fill three dump trucks.

While it was the biggest landslide he has seen in 37 years of watching the campus beach, Sylvester said the event comes as no surprise.

Since he began measuring in 2001, the cliffs have eroded at a rate of about one foot per year. If this rate continues, he said, Lagoon Road may face erosion danger in 25 years, while erosion may threaten Anacapa Residence Hall]] in approximately 50 years.

Similar to the geological forces acting on the Isla Vista bluffs, Sylvester said a combination of storms, weak rock, irrigation, plant roots, ground squirrel tunnels and wave erosion are responsible for the eroding of the campus bluffs.

“I don’t know if it’s going to come down in the next week, year, or five years,” he said. “[But] it’s going to come down.”

Aside from the future of campus buildings, Sylvester said he is presently more concerned with beachgoers’ safety.

As he was standing on the beach explaining the dangers of cliff erosion, a group of about six children began climbing and playing on the debris from the landslide. Several sunbathers lay two feet from the side of the cliff, where small pieces of rock and dirt fell to the sand. From above, joggers passed by the edge of the cliff where the fence, once several feet back from the verge, was almost hanging in midair.

He approached one beach visitor whose towel rested about a foot away from the landslide. After asking if he knew about the potential danger he had placed himself in, the man picked up his stuff and moved to a safer distance.

Sylvester said beachgoers should be more aware of their surroundings.

“These rocks are loose,” he said. “A rock can roll and twist an ankle or come down on [your] head. It’s not that they’re ignorant, it’s that they’re unaware of what the earth can do.”

Due to a general lack of knowledge about the intensity of beach erosion, the university has been unwittingly “cutting off its options” with every new building it constructs, Sylvester said. If erosion causes the cliffs to reach Lagoon Rd., service trucks will be unable to drive to the chancellor’s house, the Marine Science Institute or the residence halls, Sylvester said.

“They’ve just been filling in all the spaces with these great big buildings and giving no space to take a good sized road interior into the campus,” he said.

The cliffs have not always been in as much danger from erosion as they are currently. In the 1950s, Sylvester said the waves could easily reach the cliffs, as they do now at high tide. The 1969 El Niño winter weather pattern, however, washed sand and rocks loosened by a fire in the Santa Ynez mountains down to the shore, widening the campus beach substantially.

In a photograph Sylvester took in 1975, the beach reaches out for a distance three times its current length. In the photo, a dog runs across a now-submerged volleyball court.

“The beach was broad; it was stable enough that plants grew all over it,” he said. “Students had volleyball courts and big concrete [fire pits] all over it. The trees down here grew abundantly. There used to be two big trees down here — now there’s only one.”

During the 1983 El Niño, the sea reclaimed the wide stretch of sand. Today, the top of a fire pit students once used to roast marshmallows can be seen just below the water several yards into the ocean.

“[El Niño] took away all the sand that prevented the waves from going up and banging against the cliff,” he said. “Now, the waves are free to come up against the cliff any old time they want to.”

Surfers could once walk down the side of the cliff to the water’s edge, Sylvester said, but that slope has since been replaced by a sheer drop-off thanks to the action of the intense hydraulic pressure created by the waves. Similar to the stretch of coast running parallel to Del Playa, the bluff is made of a weak rock called “shale,” clay and topsoil. The power of wave erosion — second only in strength to glacier erosion, Sylvester said — can easily break off sections of this formation.

The waves on the east campus beach hit the sand at an angle, which causes the water to continually move sand down the coast into the Santa Barbara Harbor, he said. Waves also wash away evidence of their own influence. Walking along the beach, visitors can see pebbles, fist-sized rocks and dirt crumble from the side of the cliff – debris that is swept away when high tide rolls in.

Plants are another contributor to the cliff’s destruction, Sylvester said. He said the roots of the pampas grass and ice plants that line the top of the bluffs penetrate the weak rock of the cliff, cracking it into pieces. Because of the intensity of this winter’s rains, the plants and their roots are “growing like mad,” he said.

Cracks can also originate from the tunnels dug by ground squirrels. Rainwater, water from irrigation and water drained from other parts of the campus to the cliff flow into the cracks, causing further erosion by wedging the rock pieces apart, he said.

After penetrating the cliff’s surface, most of the water is absorbed by the underlying clay, blocking it from seeping deeper into the bluff, Sylvester said. However, he said this creates another problem because the now-wet clay layer begins to slide laterally from atop the shale layer.

Even the salty Santa Barbara air is causing the cliffs to fall away, Sylvester said.

“When that sea air blows in here and the water evaporates, it leaves a little bit of salt behind and the salt can expand when it crystallizes,” Sylvester said. “That will also help force apart the cracks in the rocks.”

There are about two-dozen photographs on Sylvester’s website through the Geology Dept. detailing the past of the cliffs. Although he has extensively measured the cliffs for the past four years, he said he is unsure as to when and if natural processes would once again create a large and accessible beach like the one in 1975.

“This is a geological process, which operates on geologic time, not human time,” he said. “It’ll go when it’s ready. I can’t tell you what it’s going to do. Or when it’s going to happen… What we can expect to happen in the future comes from what we know has happened in the past.”