The single remaining natural bridge at Natural Bridges State Beach is better described as a sea arch. Photos by Andrew Alden.

Natural Bridges State Beach is in Santa Cruz, just west of downtown. It's an easy outing and a nice spot, popular for its sheltered beach and butterfly trees. But the official park site says nothing about the rocks, so I must remedy that.

First of all, there's only one natural bridge at Natural Bridges, a sea arch next to a bedrock promontory.

The gap between these two landforms used to be a second arch, and beyond them was a third. People used to drive out on the arches and have picnics. This was around the same time that Yosemite conducted public bear feedings and dumped bonfires over the cliffs every summer evening. Now park systems take preservation more seriously, and the remaining arch is off limits. Even so, the sea will take it down some day, as it did the other two, but without human help this time.

Notice the flat surface of the surrounding land. All of this is the lowest of Santa Cruz's famous marine terraces, carved by the ocean waves some 80,000 years ago when the land lay lower and the sea level was steady. Since that time the sea has fluctuated and the land has risen. Several older terraces lie higher along the coast. The terraces are topped with a thin layer of beach sand and gravel. Today's seacliffs expose the older rock beneath. And with that, let's look at the geologic map of the area (from U.S. Geological Survey Open-File Report 97-489).

Unit Qcl is the lower terrace and Qcu is the higher terraces. Around Soquel Creek are wetland deposits (Qb) and river sediment or alluvium, shown by the lightest color. There are three units of proper rock; from left to right (and oldest to youngest) they're the Santa Margarita Sandstone (Tsm), the Santa Cruz Mudstone (Tsc) and the Purisima Formation (Tp). (We met the Purisima before at Fitzgerald Preserve, San Gregorio Beach and Point Año Nuevo.) Together they date from late Miocene to Pliocene time, about 10 million to 4 million years ago. The reason they crop out in this pattern is apparent in the photo above the map: the rock beds are tilted down to the east, which allowed erosion to expose the older rocks in the west. They got their tilt as this part of California was carried north along the San Andreas fault system.

These facts matter in understanding what you'll see as you approach the bluffs west of the arch and observe the remarkable speckled rock of the Santa Cruz Mudstone.

The underlying Santa Margarita Sandstone is full of organic matter. Beneath it, the Monterey Formation is even more so (it's the foremost of the Bay Area's petroleum source rocks). So for many thousands of years, natural gas and hydrocarbons have been rising through the Santa Cruz Mudstone, both before and after it turned from sediment to stone. They followed a set of millions of parallel cracks, or joints, made by the stresses of moving along the San Andreas fault. After that, chemically active water did the same, depositing iron minerals in the stone. You'll see that the iron mineralization is closely related to the jointing.

In at least two places, you'll find small faults displacing the Santa Cruz Mudstone. These are classified as normal faults, steep faults that drop one side relative to the other. They show nice examples of the upward-splaying pattern called flower structure, a sign that the faulting occurred near the ground surface.

These faults dropped the rocks down on the east side, reinforcing the eastward tilt of the bedding. About a half-mile east of the park, in the bluffs along West Cliff Drive, the top of the Santa Cruz Mudstone comes into view and we can see what all those rising hydrocarbons were doing: feeding a large seafloor ecosystem based on cold seeps. The UC Santa Cruz geology club visited the "toilet bowls" in 2003 and put up pictures, and a UCSC research team described them in detail in the journal Geology in 2001. Such things must exist today in similar places, like the seafloor off Santa Barbara and beneath the Gulf of Mexico.

QUEST treks into the old growth redwood forest in search of the Pacific Banana Slug, Ariolomax dolichophallus.

The slow, small, but quite vibrant life on the forest floor can often go completely unnoticed as we hustle and bustle past on our hiking trips, picnics or family outings.  Often times the little world on the ground is misinterpreted as insignificant. If noticed at all, a mushroom, snail or salamander might only capture our interest for a short while before the pull of seeing something new draws us away.  Patience is not a trait most of us humans possess enough to truly appreciate the goings on in the tiny world of the seemingly unhurried.

A common misconception then is people just aren’t that interested in things that are little, sluggish and quiet. They want big, fast and ferocious! In the wildlife film world we see many movies about lions, cheetahs, grizzly bears, wolves or elephants.  Heck, one cable channel devotes an entire week each year just on sharks.  This isn’t a bad thing.  The charismatic mega-fauna and the world they inhabit fascinate us.  It’s natural.  But taking the time to discover the small world beneath our feet can have its benefits as well.  And looking down through a different lens can provide some wonderful little surprises- a cluster of convergent ladybugs beneath a fallen leaf, redwood sorrel opening with the shade, or a spinning spider’s elaborate web catching a breeze in the glistening sun.  There is a whole community of life under each rock, little gems left for those who are careful and take the time.

It is for this that we set out on our adventure into the misty redwood canopy in hunt of a slug – The Pacific banana slug to be exact.  They are not fast but can be surprisingly elusive.  Belonging to the genus Ariolomax, there are three main species of banana slugs; columbianus, californicus and dolichophallus, – as well as two other known subspecies.  Most banana slugs live in the temperate rainforests and fog-zones of the Pacific Coast.  Banana slugs’ size, shape and coloring reflect their name as most tend to be long and yellow, some having brown or black spots.  However, they can also be light-brown, greenish, perhaps black, or even white. They are the second largest slug in the world and can grow up to ten inches long.  Banana slugs serve an important role in the forest ecosystem.  Feeding on detritus, (fallen leaves, mushrooms and even dead animals) they recycle nutrients and help replenish the soil

Since the banana slug is the official mascot of UC Santa Cruz, it seemed only fitting that we explore the mountains near campus for our quarry.  The particular species in those parts is Ariolomax dolichophallus, which, as we learn in our story, stands out among other slugs in a number of different ways.

Most people think slugs are kinda icky. And who wants to see a slow slimy boring slug anyway?  Capturing the true character, movement and, yes, beauty of the slugs is a challenge.  Luckily, QUEST has an expert in our ranks.  Prior to joining the QUEST team, Associate Producer Joshua Cassidy gained a lot of experience portraying the life and beauty of the creatures and places that are often overlooked.  In his award-winning film Life By The Tide, Josh was able to show the surprisingly vibrant life hidden among the small tide pools of Fitzgerald Marine Reserve.

Josh took his experiences in the tide pools out into the forest on our hunt for slugs. Filming a sea star slowly crawling down a mussel bed has a lot of similarities to capturing a banana slug moving up a tree trunk. “One advantage to shooting these creatures is they’re not going to fly or run away,” says Josh.  “But it will get startled and you can see that with the banana slugs.  But in order to get a good shot, you have to get close.   So, often I’ll set up in front of the animal and anticipate where it is going to go.  It takes patience and you get failed shots but you get pretty good at predicting how they are going to move.”  Josh says another key to getting a great shot is a willingness to get down on your belly in the mud.  “Something like a banana slug from a human’s eye level, say 5 feet, doesn’t look like it’s moving- doesn’t look like it’s doing very much at all.  But if you get down to the slug’s eye level and fill your frame, you see a lot more motion and activity.”  “We used a close-up filter, which is basically a magnifying glass, which allows you to get really close and pick up great detail and the unusual anatomy… As if you were another banana slug running into this gentleman.”

Through the lens of Josh’s camera we see the forest floor come alive.  And through his patience we can see the life of a banana slug in a whole new light.

See Josh’s film “Life By The Tide” or watch a shortened version of it here on QUEST TV, in a new feature called “Your Videos On QUEST.”

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^{The tsunami of March 11 broke docks and damaged boats in Santa Cruz Harbor. Most earthquake-generated tsunamis in this part of California will cause similar levels of damage. Photo courtesy Sequoia Hughes of Flickr under Creative Commons license.}

Last week the Bay Area got a tiny taste of Japan's seismic disaster when tsunami waves stirred our waters, a giant agitating the San Francisco Bay and coast with a flick of its pinky. The waves we saw overwhelming the east coast of Honshu were attenuated to small surges here at the opposite side of the Pacific Ocean.

In central California, we will always have good warning of these big seismic tsunamis because they are not created nearby. Our tectonic setting is not conducive to Japan or Sumatra-style tsunamis. But I said seismic tsunamis, the ones that earthquakes cause. There are two other kinds that mean you should always practice tsunami awareness when you're at the beach. And National Tsunami Awareness Week, scheduled by purest coincidence for next week, is a good occasion to train yourself and your family.

Standard tsunami awareness is pretty simple, simple enough to put on a sign that says, "In case of earthquake, go to high ground or inland."

_{Photo courtesy Bruce Manchon, all rights reserved}

That refers to an earthquake that you feel, not one you hear about on the radio. I can be a little more specific. Don't worry about small earthquakes, namely the short, sharp shocks we feel often around here. Worry about a long-lasting earthquake, one with slow rhythms. If one of those happens while you're at the beach, look—you want to leave anyway, because a large earthquake like that may mean trouble at home. If the sea starts acting strange, do what the sign says, period. Otherwise, follow your usual earthquake protocol: Get away without dawdling, drive warily with your radio on, remember your family plan, use your phone no more than absolutely necessary.

The tsunamis that arrive from distant quakes, or teletsunamis, come with several hours of warning. The nearest earthquake faults that could send a damaging tsunami our way—subduction zones—are off northernmost California, part of the Cascadia seismic zone that stretches up the Oregon and Washington coast into Canada. A tsunami arising from a magnitude-8 or larger event up there would arrive here at least a couple hours later. Tsunamis from major earthquakes in Alaska, far eastern Russia, Japan and the Philippines will give us much longer warning times. There are enough people on a typical beach, with phones and text devices and radios, that you should be able to count on sufficient warning even for a Cascadia event. In addition, local emergency responders will be out in person to warn beachgoers. (If you're on the beach alone, be more alert.)

If you hear about an approaching tsunami, I must advise you: don't be irresponsible and rush to the beach. We're all intrigued by geological phenomena, and every red-blooded geologist has "witness a tsunami" on his or her geological bucket list. But remember the person taking pictures at Crescent City (a town also ravaged by a tsunami from the 1964 Alaska earthquake) who was washed out to sea. Think about the surfers who wandered around Santa Cruz Harbor, risking themselves and worrying others, as the waters rushed in and out.

However, if you choose to ignore my advice, then you should do as I wish I could have done, and proceed in a responsible manner to a safe place high above the water, obeying authorities, not congesting emergency escape routes, prepared for the worst. UC Santa Cruz geologist Christie Rowe did that and recorded the tsunami's arrival. She adds, "I would advise people not to panic, to check the West Coast Tsunami Warning Center website and select a vantage point well above the predicted wave height."

But not every tsunami is a seismic tsunami. Two other kinds of tsunamis, not monitored by dedicated networks, have a chance of happening somewhere in the world during the average lifetime: landslide and impact tsunamis. A landslide tsunami, caused by large mass movements into or beneath the sea, is quite plausible along our steep coasts and rugged offshore seafloors. Be wary of one even after a relatively small local quake. An impact tsunami, caused by an object from space crashing into the ocean, has no upper size limit and no preferred location. The odds are small but every beach in the world, ours included, faces the risk. So be like a sailor and always keep your weather eye out.

Learn more:
California tsunami information
National Tsunami Awareness Week
tsunami.gov
West Coast/Alaska Tsunami Warning Center

And check out QUEST's story "Scary Tsunamis":

QUEST on KQED Public Media.

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 Albino Redwoods Educator Guide

UC Santa Cruz plant biologist Jarmila Pitterman and her students are studying rare albino redwood trees in the Santa Cruz Mountains to better understand the inner workings of these unusual plants. By learning how albino redwoods survive, they may unlock some of the mysteries of how redwood trees live and how they will weather things such as disease, drought or climate change.

Quest Educational Resources

 Print Guide - Natural Bridges State Beach

 Natural Bridges State Beach KML file

 Tips to get the kids in your life out into nature

 Designing an Exploration on Google Maps

Additional Links

• LiMPETS: Long-term Monitoring Program & Experiential Training for Students
• Make a Tide Prediction, California
• Natural Bridges State Beach official website

You may listen to the "California's Fire Future" Radio report online, as well as find additional links and resources.

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Quest Educational Resources

 Print Guide - Natural Bridges State Beach

 Natural Bridges State Beach

 Tips to get the kids in your life out into nature

 Designing an Exploration on Google Maps

Additional Links

• Natural Bridges State Beach official website