South Coast Geological Society

Meetings

Register for January Meeting HERE

Please join South Coast Geological Society and San Diego Association of Geologists for our joint meeting on Tuesday, January 15th, 2019 at 5:30 PM to be held at the Green Dragon Tavern and Museum in Carlsbad, CA (6115 Paseo del Norte, Carlsbad, CA 92011, Tel: 760.918.2421). We are hosting three guest speakers, Dr. Ken Hudnut, Matt Burgess, and Diane Murbach who will present their topic: “A Landscape Altered: The Explosive End to Kilauea’s Summit Lava Lake and the Lower East Rift Zone Eruption of 2018.”

Abstract 1: Kīlauea is a basaltic shield volcano located on the Island of Hawaiʻi characterized by a summit caldera and two radiating rift zones. Currently ranked by the USGS as the number one threat for U.S. volcanoes, along with Etna and Piton de la Fournaise (Reunion Island), it ranks among the world’s most active volcanoes and is often considered the most active volcano on Earth. Kīlauea, which is built on the east flank of the massive Mauna Loa volcano, has been Hawaii’s most active volcano during historical time. Once thought to be a mere satellite of its giant neighbor, research over the over the past few decades shows that Kīlauea has its own magma plumbing system, extending to the surface from more than 37 miles deep in the mantle. It lies along the Kea trend of magmatic composition, chemically similar to Mauna Kea, Kohala, Haleakalā (Maui), West Maui and east Molokaʻi and chemically distinct from the sub-parallel Loa trend volcanoes: Lōʻihi, Mauna Loa, Hualālai, Māhukona, Kaho’olawe, Lānaʻi, west Molokaʻi and Koʻolau (Oʻahu).

Abstract 2: Eruptions are prominent in Polynesian legends as the volcano is home to the deity Pele, who isrevered in Hawaiian culture; and though written documentation only extends back to 1820, itrecords frequent summit and flank lava flow eruptions interspersed with periods of long-termlava lake activity. The 1.9 x 3.1 mile caldera was formed in several stages, with the most recent caldera forming period lasting about 300 years between 1500 and 1790 CE. The penultimate lava lake within the Halemaʻumaʻu crater in the summit caldera, persisted for about 100 years, ending with explosive eruptions in 1924 when an intrusion entered the lower East Rift Zone.Since 1952 there have been 34 eruptions on the volcano. Eruptions have also originated from the >32 mile long East and >19 mile long Southwest Rift Zones, both of which extend to the sea from the volcano’s summit. About 90% of the surface of the volcano is made up of lava flows less than 1100 years old and 70% of the volcano’s surface is younger than 600 years old. A long-term eruption from the PuʻuʻŌʻ’ō vent on the East Rift Zone that began in 1983 produced lava flows covering more than 39 square miles of land, inundating the community of Kalapana, destroying nearly 200 houses (before 2018) and adding new coastline to the island. In the spring and summer of 2018 Kīlauea underwent drastic changes in its eruption, forever altering the once familiar landscapes. The PuʻuʻŌʻō vent collapsed on April 30 and magma migrated down rift. A magnitude 6.9 earthquake occurred on the volcano’s south flank on May 4th and ~60,000 earthquakes occurred on the volcano between April 30 and August 4. Fissures formed in the populated Leilani Estates area of the lower East Rift Zone, eventually erupting ~1 billion cubic yards of lava. 716 dwellings were destroyed as 13.7 square miles of land was inundated by lava and 875 acres of new land was created by ocean entries. The lava lake in Halemaʻumaʻu, present in the Overlook vent since 2008 and overflowing onto the floor of the crater between April 22 and 28, had completely drained by May 10th, a decline of almost 1000 ft. Beginning on May 16 the summit vent became the site of explosive events that sent ash as high as 30,000 ft. On May 29 the caldera around Halemaʻumaʻu began to subside and near-daily summit collapse events continued until August 2nd, with each event releasing energy equivalent to that of a ~ magnitude 5 earthquake. When the dust had settled the partial collapse of the caldera had increased the area of Halemaʻumaʻu by ~1 billion cubic yards and maximum subsidence in the caldera was over 1,600 ft. By August 17th eruption of lava from fissure 8 had stopped and the ocean entries were no longer active by August 21. By September 4th when lava was no longer visible in the fissure 8 spatter cone, Kīlauea’s largest eruption in at least 200 years was at least temporarily over.

Presented by: The talk will include 3 speakers. First, Diane Murbach will discuss 40 years of chasing lava with Monte Murbach at Kīlauea, and present photographs of Pele’s 2018 lava from Fissure 8. Second, Matt Burgess will present a chronology of the 2018 eruption from the perspective of the geophysical response and third, Ken Hudnut will describe rapid topographic changes, with both Halema’uma’u and the summit caldera collapsing, and pulses of lava flowing from the Lower East Rift Zone, using helicopter-mounted lidar and aerial photography.

Speaker Bios:

Dr. Ken Hudnut has studied earthquakes as a geophysicist for the U. S. Geological Survey (USGS) in Pasadena since 1992. He recently led large team efforts to develop the HayWired Earthquake Scenario, as well as to obtain high-resolution topographic data using helicopter-mounted lidar to assess the eruption of Kilauea volcano. To help understand the San Andreas Fault system and the behavior of faults in general, he has studied earthquakes worldwide using satellite & airborne imagery along with field work to provide ground truth. Recently, he receivedawards for distinguished service and leadership from the American Geophysical Union and for meritorious service from the U.S. Department of the Interior. He is a Visiting Associate in Geophysics at Caltech and a Lecturer (on engineering geology) in Civil & Environmental Engineering at UCLA. He received his Ph.D. from Columbia in 1989, and his A.B. (high honors) from Dartmouth in 1983.

Matt Burgess was the seismic analyst for the USGS Hawaiian Volcano Observatory from 2013 – April 2018. On May 4th, 2018 he was called into emergency service for the USGS response to the eruption of Kīlauea volcano. For the following five weeks he stood watch 12 -15 hours per day over streaming real time geophysical data, providing situational awareness on the eruption from seismic, infrasound, deformation and atmospheric radar reflections off the tops of ash columns to Observatory staff in the field and Emergency Operations Command from his homein San Diego. He has a MS in Geological Sciences from SDSU (2008) and has previously worked for the USGS California Water Science Center, San Diego Natural History Museum as well as on geophysics research projects at Mt. St. Helens, Long Valley Caldera, volcan Villarrica in Chile and the Alpine Fault, New Zealand. He is currently parenting full time, a volunteer research associate with the Hawaiian Volcano Observatory studying patterns of seismicity on Kīlauea and Mauna Loa, volunteering with the Guza lab coastal studies LiDAR group at ScrippsInstitution of Oceanography, and looking for meaningful long term employment in the geological sciences in San Diego.

Diane Murbach is a Certified Engineering Geologist (CEG) with 35 years of experience and registered in the States of California, Oregon, Washington and Arizona. She is a principal engineering geologist working as a co-owner of Murbach Geotech (MG) with her husband Monte Murbach. Diane received a B.S. degree from Eastern Washington University and an M.S. degree from San Diego State University in Geology. Diane’s volunteer work for geologicalsocieties includes being a past President for the San Diego Association of Geologists (SDAG), and the South Coast Geological Society (SCGS). She currently serves as Secretary on the Board of Directors for the San Diego Geological Society, Inc., and chair for the Earth Science working group updating the San Diego Tijuana Earthquake Planning Scenario. Diane’s background with volcanoes began in 1979 with Monte when both attended a two week Geology of Hawaii class on the Big Island. Six months later both were on another geology class next to Mount St. Helens in the state of Washington when this stratovolcano erupted. Diane and Monte have been chasing volcanoes and visiting all the Hawaiian Islands for the past 40 years.

Menu: Herb Grilled Chicken Breast, Vegetarian Cheese Ravioli, Classic Caesar Salad, Vegetable Medley, Garlic Mashed Potatoes, Bread Rolls, Cheesecake.