Earthquake-Volcanic Eruption Report: Hawai’i

My USGS Earthquake Notification Service email inbox has been going on overtime.

There has been a swarm of earthquakes on the southeastern part of the big island, with USGS volcanologists hypothesizing about magma movement and suggesting that an eruption may be imminent. Here is a great place to find official USGS updates on the volcanism in Hawaii (including maps). I had been following this on social media.

Hawaii is an active volcanic island formed by hotspot volcanism. The Hawaii-Emperor Seamount Chain is a series of active and inactive volcanoes formed by this process and are in a line because the Pacific plate has been moving over the hotspot for many millions of years.

As these volcanoes grow with time, the flanks of the volcanoes become covered in new volcanic rock. The flanks become unstable and collapse as landslides. There is evidence that some of these landslides trigger some of the largest tsunami ever found.

The seismicity started in the central part of the “East Rift Zone” (ERZ), a region of extension probably caused by flank collapse. This extension lowers pressure in the magma chamber, leading to eruptions. Magma migrates around for various reasons, including changes in pressure in the magma chamber. These motions of magma and fluids can cause earthquakes.

This part of Hawaii is the locus of the most recent volcanism, with the newest volcanic center formed to the southeast of the island.

Southeast of the main Kilauea vent, the Pu‘u ‘Ö‘ö crater saw an elevation of lava into the crater, leading to overtopping of the crater (on 4/30/2018). Seismicity migrated eastward along the ERZ. This morning, there was a M 5.0 earthquake in the region of the Hilina fault zone (HFZ). I was getting ready to write something up, but I had other work that I needed to complete. Then, this evening, there was a M 6.9 earthquake between the ERZ and the HFZ.

There have been earthquakes this large in this region in the past (e.g. the 1975.1.29 M 7.1 earthquake along the HFZ). This earthquake was also most likely related to magma injection (Ando, 1979). The 1975 M 7.1 earthquake generated a small tsunami (Ando, 1979). These earthquakes are generally compressional in nature (including the earthquakes from today).

Today’s earthquake also generated a tsunami as recorded on tide gages throughout Hawaii. There is probably no chance that a tsunami will travel across the Pacific to have a significant impact elsewhere.

So. This M 6.9 may be the largest earthquake. There may be a larger one in store (the USGS suggests that these fault systems could produce a M 8 earthquake). The eruptions may be done for now. There may be more.

Below is my interpretive poster for this earthquake

I plot the seismicity from the past month, with color representing depth and diameter representing magnitude (see legend). I include earthquake epicenters from 1918-2018 with magnitudes M ≥ 4.5 in a second poster (and down to M ≥ 3.5 in a third poster).

I plot the USGS fault plane solutions (moment tensors in blue and focal mechanisms in orange) for the M 6.9 earthquake, in addition to some relevant historic earthquakes.

I placed green circles in the locations of the (a) 4/30 lava lake filling event and (b) 5/3-4 fissure eruption.

  • I placed a moment tensor / focal mechanism legend on the poster. There is more material from the USGS web sites about moment tensors and focal mechanisms (the beach ball symbols). Both moment tensors and focal mechanisms are solutions to seismologic data that reveal two possible interpretations for fault orientation and sense of motion. One must use other information, like the regional tectonics, to interpret which of the two possibilities is more likely.
  • I include some inset figures.

  • In the upper right corner is a geologic map with color representing the relative age of volcanic deposits (Sherrod et al., 2007). (red = youngest, orange next youngest) I placed a blue circle in the location of the vents that erupted on 5/3-4.
  • In the upper left corner is a map that shows the rift zones (active extensional volcanism) and the region is divided by the major sources for the volcanic rocks (e.g. Mauna Kea, Mauna Loa, and Kilauea; Tilling et al., 2010). I placed a blue circle in the location of the vents that erupted on 5/3-4.
  • In the lower left corner is a visualization showing the magma reservoir hypothesized to be the source of lava along the Southwest and East Rift zones, as well as for Kilauea (Tilling et al., 2010).
  • In the lower right corner is a map that shows the relative severity of volcanic hazard for the island of Hawaii (Tilling, et al., 2010).
  • To the left of the hazard map is a geological cross section showing the subsurface structures in the region (USGS).

  • This version includes earthquakes M ≥ 4.5

  • This version includes earthquakes M ≥ 3.5 (note the seismicity offshore to the south, this is where the youngest Hawaii volcano is).

USGS Earthquake Pages

  • I put together a short video that shows seismicity from the past month. This reveals how the magma may have moved throughout the region between 4/27 and 5/4. Here is a link to download the ~8 MB mp4 video file.

Some Relevant Discussion and Figures

  • Here is the map showing the rifts (Tilling et al., 2010)

  • Shaded relief map of the southeastern part of the Island of Hawai‘i, showing the principal features and localities of Mauna Loa, Kïlauea, and Lö‘ihi Volcanoes discussed in the text.

  • This is the figure that shows an hypothetical configuration of the magma reservoir beneath Kilauea (Tilling et al., 2010).

  • Cut-away view looking deep beneath Kïlauea Volcano, showing the shallow magma reservoir and the principal magma passageways. Areas in yellow are the most favorable zones for magma movement (arrows show direction) and storage. Though greatly generalized, this depiction of Kïlauea’s “plumbing system” is compatible with all known scientific information. (Simplified from technical illustration of Michael P. Ryan, USGS.)

  • Below are a series of plots from tide gages installed at several sites in the Hawaii Island Chain. These data are all posted online here and here.
  • Hilo, Hawaii

  • Kawaihae, Hawaii

  • Here is a plot showing the tsunami from the 1975 M 7.1 earthquake (Ando, 1979). On the left are modeled tsunami wave height based on two different fault models (each with fault dips of 20 degrees, but widths of 20km and 30km).

  • This is a timeline of historic volcanism on Hawaii (Tilling et al., 2010).

  • Graph summarizing the eruptions of Mauna Loa and Kïlauea Volcanoes during the past 200 years. The Pu‘u ‘Ö‘ö- Kupaianaha eruption has continued into the 21st century. Information is sketchy for eruptions before 1823, when the first missionaries arrived on the Island of Hawai‘i. The total duration of eruptive activity in a given year, shown by the length of the vertical bar, may be for a single eruption or a combination of several separate eruptions.

  • Here is the volcanic hazard severity map from Tilling et al. (2010).

  • Map of Island of Hawai‘i showing the volcanic hazards from lava flows. Severity of the hazard increases from zone 9 to zone 1. Shaded areas show land covered by flows erupted in the past two centuries from three of Hawai‘i’s five volcanoes (Hualälai, Mauna Loa, and Kïlauea).

  • Below is a series of maps that shows the recent volcanism in the region (Orr et al., 2012).

  • The first 3½ years of the Pu‘u ‘Öÿö eruption of Kïlauea Volcano (January 1983–June 1986) were dominated by episodic lava fountains that constructed the Pu‘u ‘Öÿö cone and fed ‘a‘ä flows (the less fluid of the two types of Hawaiian lava flows) (USGS photo by J.D. Griggs, June 1984). The map shows lava flows erupted from Kïlauea Volcano in the 19th and 20th centuries (gray). These flows originated from the summit caldera, the East Rift Zone, or the Southwest Rift Zone (not shown). Flows erupted during the first 3½ years of the Pu‘u ‘Öÿö eruption are shown in red. The Island of Hawai‘i (see inset map) is composed of five volcanoes—Kohala, Mauna Kea, Hualälai, Mauna Loa, and Kïlauea

    In 1986, the Pu‘u ‘Öÿö eruption shifted to the Kupaianaha vent. This photo shows lava flows erupted from Kupaianaha entering the community of Kalapana on the Island of Hawai‘i’s southeast coast in May 1990 (USGS photo by J.D. Griggs). Over the following months, Kalapana was almost completely destroyed, and lava filled beautiful nearby Kaimü Bay. The map shows lava flows erupted from Kupaianaha and nearby fissures during 1986–1992 in red. Older flows from the Pu‘u ‘Öÿö eruption are shown in orange.

    Lava flows erupt from new vents on the south flank of the Pu‘u ‘Öÿö cone (right side of photo) that opened after Pu‘u ‘Öÿö Crater filled to overflowing in early 2004 (USGS photo by Richard Hoblitt, January 2004). Collapse of the southwest side of the cone formed a scallop-shaped scar, revealing red layers of welded spatter (deposited as clots of molten lava) that under-lie loose tan-colored pyroclastic deposits (hot debris ejected during an eruption). The map shows flows erupted from Pu‘u ‘Öÿö and from fissures in Näpau Crater during 1992–2007 in red. Older flows from the Pu‘u ‘Öÿö eruption are shown in orange.

    A lava channel, elevated as much as 150 feet (45 meters) above the adjacent terrain, transports lava away from the Fissure D vent, which opened in July 2007 (USGS photo by James Kauahikaua, October 2007). The “perched” (elevated) lava channel was the main path for lava until November 2007, when lava was diverted from the vent to the southeast. Pu‘u ‘Öÿö is at upper right. The map shows lava flows erupted in Pu‘u ‘Öÿö and from the Fissure D vent between Pu‘u ‘Öÿö and Kupaianaha during 2007–2011 in red. Older flows from the Pu‘u ‘Öÿö eruption are shown in orange.

    In March 2011, lava broke to the surface between Pu‘u ‘Öÿö and Näpau Crater marking the start of the Kamoamoa fissure eruption. In this photo lava erupts from the fissure shortly after the beginning of the eruption and pours into a deep, older crack (USGS photo by Tim Orr). The map shows flows erupted during the Kamoamoa eruption and from Pu‘u ‘Öÿö during 2011–2012 in red. The Kamoamoa flows are to the left, flows from the August 2011 Pu‘u ‘Öÿö flank breakout are at center, flows from a fissure high on Pu‘u ‘Öÿö’s northeast flank are to the right. Older flows from the Pu‘u ‘Öÿö eruption are shown in orange.

  • This map highlights the seismicity associated with volcanism related to the youngest volcano in the Hawaii Islands (Tilling et al., 2010).

  • Map showing the locations of earthquakes that occurred during the 1970s and in the July–August 1996 period in the vicinity of Lö‘ihi. These earthquake swarms, plus similar occurrences in 1984–85 and the early 1990s, provide seismic evidence that Lö‘ihi is an active submarine volcano.

  • The ERZ and HFZ are also actively deforming between earthquakes. Below are two maps that show (a) regional vertical land motion and (b) results from block modeling to resolve the differential motion across this area (Shirzaei et al., 2013).

  • The linear velocity field in the line of sight of the descending-orbit Envisat satellite (track 200) over the Kilauea south flank from 2003 till 2010. Area of the study, Hilina Fault System (HFS), is outlined by dashed box. Location of GPS stations used is marked by their names next to filled squares colored by the mean rate of motion in the LOS direction. Station PGF1 is the reference for both GPS and InSAR datasets. WHP = western Hilina Pali, HP = Holei Pali.

    Colored panels represent relatively coherently moving blocks based on the InSAR deformation over the HFS according to Figs. 2–4 and traces of mapped faults, which are used to compare with GPS data. Each block is labeled by its average LOS velocity.

Geologic Fundamentals

  • This is an image from the USGS that shows how, when an oceanic plate moves over a hotspot, the volcanoes formed over the hotspot form a series of volcanoes that increase in age in the direction of plate motion. The presumption is that the hotspot is stable and stays in one location. Torsvik et al. (2017) use various methods to evaluate why this is a false presumption for the Hawaii Hotspot.

  • A cutaway view along the Hawaiian island chain showing the inferred mantle plume that has fed the Hawaiian hot spot on the overriding Pacific Plate. The geologic ages of the oldest volcano on each island (Ma = millions of years ago) are progressively older to the northwest, consistent with the hot spot model for the origin of the Hawaiian Ridge-Emperor Seamount Chain. (Modified from image of Joel E. Robinson, USGS, in “This Dynamic Planet” map of Simkin and others, 2006.)

  • Here is a map from Torsvik et al. (2017) that shows the age of volcanic rocks at different locations along the Hawaii-Emperor Seamount Chain.

  • Hawaiian-Emperor Chain. White dots are the locations of radiometrically dated seamounts, atolls and islands, based on compilations of Doubrovine et al. and O’Connor et al. Features encircled with larger white circles are discussed in the text and Fig. 2. Marine gravity anomaly map is from Sandwell and Smith.

  • Here is a great educational video from the USGS that discusses eruptions in 2011, which were similar in type and style of eruptions as the current phase of eruption. Here is a link to the 4 MB mp4 video file.
  • For more on the graphical representation of moment tensors and focal mechanisms, check this IRIS video out:
  • Here is a fantastic infographic from Frisch et al. (2011). This figure shows some examples of earthquakes in different plate tectonic settings, and what their fault plane solutions are. There is a cross section showing these focal mechanisms for a thrust or reverse earthquake. The upper right corner includes my favorite figure of all time. This shows the first motion (up or down) for each of the four quadrants. This figure also shows how the amplitude of the seismic waves are greatest (generally) in the middle of the quadrant and decrease to zero at the nodal planes (the boundary of each quadrant).

  • There are three types of earthquakes, strike-slip, compressional (reverse or thrust, depending upon the dip of the fault), and extensional (normal). Here is are some animations of these three types of earthquake faults. The following three animations are from IRIS.
  • Strike Slip:



Social Media



  • Ando, M., 1979. The Hawaii Earthquake of November 29, 1975: Low Dip Angle Faulting Due to Forceful Injection of Magma in JGR, v. 84, no. B13
  • Orr, T.R., et a., 2012. The Ongoing Pu‘u ‘Ö‘ö Eruption of Kïlauea Volcano, Hawai‘i—30 Years of Eruptive Activity in USGS Fact Sheet 2012-3127, 2013.
  • Sherrod, D.R., Sinton, J.M., Watkins, S.E., and Brunt, K.M., 2007, Geologic Map of the State of Hawaii: U.S. Geological Survey Open-File Report 2007-1089, 83 p., 8 plates, scales 1:100,000 and 1:250,000, with GIS database
  • Tilling, R.I., Keliker, C., and Swanson, D.A., 2010. Eruptions of Hawaiian Volcanoes—Past, Present, and Future, U.S. Geological Survey, General Information Product 117, 72 pp.
  • Torsvik, T.H., et al., 2017. Pacific plate motion change caused the Hawaiian-Emperor Bend in Nature Communications, DOI: 10.1038/ncomms15660
Category(s): earthquake, education, geology, pacific, plate tectonics, volcanoes

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