Dear friends and customers of FGS,

Welcome to the fall issue of News and Research, the newsletter of the Florida Geological Survey. As you may be aware, the FGS has relocated its headquarters. Our previous location is making way for an expansion of the Florida State University campus. The story of our previous headquarters, in which the FGS operated from 1957 to 2015, is fascinating and I am pleased to share it with you in this issue. As is the norm, this issue also highlights a selection of our recent and ongoing activities, as well as our quarterly GEOFACT.

The focus of our GEOFACT in this issue is tsunamis. We all remember the videos and devastation of Japan’s Tōhoku tsunami in 2011; however, we do not often hear “Florida” and “tsunami” in the same sentence. This is because conditions that cause these enormous waves are not common in the southeastern Atlantic Ocean or the Gulf of Mexico. That being said, Florida does have a low-lying topography, 1,350 miles of coastline and more than 8,400 miles of tidally influenced shoreline. We rank third in the nation in coastline length. Given these characteristics, FGS does stay up-to-date regarding the fascinating phenomena of tsunamis and their historical record in our part of the world.

In closing, I invite you to participate in our FGS Open House on Friday afternoon, October 16, which coincides with the last day of Earth Science Week. We will be offering tours of our new facility, and hands-on activities for budding geoscientists. Earth Science Week is celebrated nationwide and is a great time to either do your part as a steward of the geosciences or participate in local activities. My personal passion for geology began when I was about six years old, and was ignited by family members plus an enthusiastic welcome to the world of “rockhounding” by our local gem and mineral society. Please take time to consider what you can do to open a similar door for a young scientist. As a start, perhaps forward this newsletter to a teacher or student who may be interested, or perhaps a church or scouting group. Enjoy!

Best Regards,

Jonathan D. Arthur, Ph.D., P.G.
Director and State Geologist
Florida Geological Survey
Florida Department of Environmental Protection

•GEOFACT - Could Tsunamis Impact Florida?   More…

•Karst Open Research Initiative Gains Momentum... More…

•FGS Receives National Grant to Map in Jacksonville...   More…

•FGS Receives Data Preservation Grant through USGS   More…

•FGS Aquires New Flow Meter for Spring Studies   More…

•FGS Says Final Farewell to Herman Gunter Building More…

•See Previous Editions of FGS News and Research More…

A tsunami is a series of waves caused by the vertical displacement of water. Potential tsunami-generating events that might impact the coast of Florida range from large meteorite impacts in the ocean, to events such as earthquakes and underwater landslides. How likely are we to see the effects of a tsunami in Florida? It might be helpful to examine what we have learned about tsunamis throughout history to answer this question.

The majority of tsunamis are generated by earthquakes that displace portions of the seabed or by landslides caused by a seismic event. The remainder are due to volcanic eruptions or explosions. Historically, the bulk of all reported earthquakes do not occur within waters adjacent to the state of Florida, but rather in the Pacific and Indian oceans.

In 1755, an earthquake occurred off the coast of Portugal and spawned the historic “Lisbon tsunami.” This tsunami generated a series of waves which struck Barbados and Martinique in the Caribbean with a peak wave estimated to be approximately 13 feet (4 meters) high. No Florida historical records related to that tsunami have been found. Computer modeling, however, does indicate that that tsunami would have impacted the east coast of Florida north of the “protective shadow” of the Bahamas.

Some research has been done to quantify the risk of submarine landslide-generated tsunamis along the east coast of the U.S. In two studies the areas identified to be at most risk were found to lie far north and south of the Florida east coast (Dunbar and Weaver 2008 and ten Brink et. al. 2014). Historical occurrences indicate that a tsunami generated by either an earthquake or a submarine landslide off the north coast of Puerto Rico would be largely dampened by islands lying north and west of Puerto Rico well before reaching the Florida coast.

Submarine landslides have occurred not just off the east coast of North America but also in the Gulf of Mexico. Within the Gulf of Mexico in 2004, Hurricane Ivan triggered an underwater landslide that substantially damaged a platform and cluster of oil wells owned by Taylor Energy Company. While that event apparently did not trigger a detectable tsunami, it does suggest the potential for the occurrence of events in the Gulf of Mexico which might generate a tsunami. The potential for such has been assessed by ten Brink et. al. (2009).

Recent research suggests that the east coast of Florida could be impacted by a tsunami generated by the volcanic eruption and collapse of any number of volcanos in the Cape Verdes, Azores and Canary Islands situated off southern Europe and Africa (Day, et. al. 1999, Ward and Day 2005 and Abadie, et. al. 2012). Debris flows from past collapses of volcanos in the Cape Verdes and Canary Islands have been identified on the sea floor adjacent to those islands. It is hypothesized that a volcanic collapse and subsequent tsunami in the Canary Islands between approximately 133,000 and 100,000 years ago might have generated sedimentary deposits, called tsunamiites, in the Bahamas. The most dramatic of these are multi-ton boulders displaced towards the land. To date, no such deposits have been identified in Florida.

The Cumbre Vieja Volcano, located on Isla de La Palma in the Canary Islands, has been identified by some researchers as being of particular concern. A massive gravitational landslide on the western side of the valcano could, according to some models, generate a series of waves that would impact the U.S. eastern seaboard and the coast of Florida north of the protective shadow of the Bahamas (Day, et. al. 1999; Abadie, et. al. 2012 and Tehranirad et al 2015 ). It should be noted that this modeling is highly conjectural and dependent upon a number of variables, including whether the slumping is a single massive, rapid coherent landslide or a series of smaller events over time.

To enable early detection of tsunamis and to gain data for forecasting, NOAA has placed Deep-ocean Assessment and Reporting of Tsunami (DART®) stations at sites depicted in red in the figure to the right. There are five DART stations off the east coast of the U.S. and one in the Gulf of Mexico. If a tsunami is generated, early warning of the wave’s arrival can be initiated and loss of life prevented.

For a bibliographic list of references cited in this article click here.

Contact person/info: Dan Phelps 

For more than twenty years, the Florida Geological Survey has been leading an effort to characterize the Upper Floridan aquifer (UFA) in the Woodville Karst Plain (WKP) region. The WKP makes an ideal field laboratory for hydrogeologic research because it exhibits all of the classic components of unconfined, karstic, coastal carbonate aquifers that typify the UFA in Florida. These components include sinking streams and swallets, sinkholes and vertical karst windows interconnected via an extensive system of underground, horizontal conduits, and the presence of numerous springs, including Wakulla Spring, one of Florida’s largest and most dramatic first magnitude springs. The numerous karstic interconnections in the WKP region produce extremely complex behaviors in the local aquifer system due to the ever-changing interplay of rainfall, groundwater use, and oceanic tidal cycles.

The Karst Open Research Initiative (KORI) is an effort by the FGS to present over a decade’s worth of high-resolution hydrologic data in a format that is easily accessible to outside researchers in a manner that facilitates the open exchange of ideas and analyses between interested parties. The public face of KORI is the project’s GitHub repository and accompanying project wiki. GitHub is an extremely popular tool for collaborative software projects, and the site’s built-in wiki functionality is a natural vehicle for sharing information and metadata with researchers that might be unfamiliar with the region. GitHub is also an ideal platform for sharing work in the geosciences, as it ensures public availability of the base computer code used to generate statistical analyses. Public availability allows researchers to easily download, critique, modify, or extend FGS’ data and analyses at their discretion.

Although underway for less than a year, the KORI project has already generated a strong interest among researchers in a diverse variety of fields and institutions. Faculty in the Florida State University Department of Earth, Ocean, and Atmospheric Sciences as well as Computer Science faculty at the University of South Carolina have already received assistance in setting up and working with copies of the FGS hydrologic data. The public availability of this data has also given the FGS a voice in directing future research in the region, as researchers interested in acquiring new hydrologic data in the area have repeatedly sought out FGS staff for expertise regarding the most effective use of the available resources.

Contact person/info: Seth Bassett or Scott Barrett Dyer  

The Florida Geological Survey has been awarded $174,005 by the U.S Geological Survey to produce a detailed geologic map of the Jacksonville 30 x 60 minute quadrangle in northeast Florida. The 2015 STATEMAP grant is the second-highest award amount distributed nationwide this year. The work will begin in September of 2015 and is expected to be publicly available for digital download by December 2016. The FGS has also completed new geologic mapping of the Orlando 30 x 60 minute quadrangle under a 2015 STATEMAP award. The Orlando mapping reports will be finalized and available by December of 2015

The benefits of this type of mapping include a more comprehensive understanding of the distribution of rock, mineral and groundwater resources, including vulnerability of aquifers to contamination. These maps are also important in providing shallow subsurface geological information that can be used in understanding sinkholes and other geologic hazards. 

The new mapping effort involves field work over a 12 month period, including visits to accessible rock and sediment exposures in mines and other excavated areas, as well as natural exposures in rivers, streams, sinkholes and springs. To better understand the underlying geologic units, project staff inspect rock and sediment samples from hundreds of wells, including new wells drilled in support of the project to fill data gaps. Extensive data management and map making in a geographic information system platform is also involved.

This work is conducted under the STATEMAP component of the National Cooperative Geologic Mapping Program, which serves to create a national geologic database that is accessible to the public. The STATEMAP Advisory Committee, which is comprised of geologists, hydrologists and engineers in Florida, prioritized the Jacksonville quadrangle as the primary focus for this year’s work.

The approximately 1,300 square mile area was approved due to its location adjacent to previous mapping in the St. Augustine area, as well as being able to leverage recent work conducted along the northeast coast of Florida funded by the National Park Service and Florida Geological Survey. This will allow the Florida Geological Survey to maximize its resources and expand upon existing data.

Since its inception in 1994, this component of the National Cooperative Geologic Mapping Program has funded more than $4.9 million in support of mapping to benefit Florida’s residents and environment, covering an area of approximately 24,000 square miles (45% of the state). STATEMAP is one of the most cost-effective programs at the FGS (average cost is $205/square mile). Economic studies of the value of geologic mapping indicate that the mapping funded by the FDEP and USGS STATEMAP Program has generated on the order of $130 Million worth of benefit for the State.

Contact person/info: Rick Green   

The FGS’ Applied Geoscience Services Section recently acquired a tool that uses acoustic frequencies to obtain flow measurements in springs and rivers. This “SonTek RiverSurveyor M9” acoustic flow meter was purchased along with a “HydroBoard II” floating/tetherable platform for deploying the instrument. Use of acoustic frequencies fused with precise bandwidth control allows for continuous shallow-to-deep discharge (flow) measurements to be obtained. The FGS opted for a number of the available upgrades (compass and GPS) that provides the capability to quickly and safely obtain accurate discharge measurements in springs and rivers during low flow conditions as well as when flood events are occurring.

Currently, the flow meter is being used to collect discharge measurements at springs in the middle Suwannee River basin for an on-going collaborative study with the Suwannee River Water Management District. It is anticipated that it will be used to collect discharge data for a dye trace study in the Alapaha and Suwannee River basins later in the year. In addition, the flow meter will allow the FGS to collect flow data for other researchers within the Department as well as outside collaborators.

Contact person/info: Tom Greenhalgh