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Using Ground Crack and Very Low Frequency Measurements to Map the Location of the June 2007 Father’s Day Dike, Kīlauea

Tim R. Orr, James P. Kauahikaua, Christina Heliker, P.M. Davis, W.A. Duffield, D. Fee · U.S. Geological Survey

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Scientific Investigations Report 2024–5030

U.S. Department of the Interior U.S. Geological Survey

Cover. Photograph of the Father’s Day (episode 56) lava flow in the forest on the northeast flank of Kānenuiohamo, hours after eruption. The lava flow was the culmination of a magmatic intrusion into Kīlauea’s upper East Rift Zone during June 17–19, 2007. Photograph by C. Heliker, U.S. Geological Survey, June 19, 2007.

Using Ground Crack and Very Low Frequency Measurements to Map the Location of the June 2007 Father’s Day Dike, Kīlauea By Tim R. Orr, James P. Kauahikaua, and Christina Heliker

Scientific Investigations Report 2024–5030

U.S. Department of the Interior U.S. Geological Survey

U.S. Geological Survey, Reston, Virginia: 2024

For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit https://www.usgs.gov or call 1–888–392–8545. For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov/ or contact the store at 1–888–275–8747. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Orr, T.R., Kauahikaua, J.P., and Heliker, C., 2024, Using ground crack and very low frequency measurements to map the location of the June 2007 Father’s Day dike, Kīlauea Volcano: U.S. Geological Survey Scientific Investigations Report 2024–5030, 44 p., https://doi.org/10.3133/sir20245030. Associated data for this publication: Orr, T.R., 2024, Ground crack, VLF measurement, and sample vesicularity data for the June 2007 Father’s Day eruption, Kīlauea Volcano: U.S. Geological Survey data release, https://doi.org/10.5066/P955VWUV. ISSN 2328-0328 (online)

iii

Acknowledgments Eruption response is a team effort, and we thank the staff, students, and volunteers of the U.S. Geological Survey (USGS) Hawaiian Volcano Observatory, the National Park Service, and the University of Hawai‘i at Hilo for the logistical support and observations that helped facilitate this research. We are grateful for the expert piloting of D. Okita of Volcano Helicopters. D. Swanson and M. Poland of the USGS Hawaiian Volcano Observatory helped with the mapping and measuring of ground cracks. Installation and measurement campaigns of the crack stations in Nāpau Crater were conducted over the years in collaboration with USGS Hawaiian Volcano Observatory scientists D. Sherrod, J. Sutton. This work was aided by USGS Hawaiian Volcano Observatory volunteers D. Weiss, D. Ahearn, R. Holm, M. Cazeneuve, D. Goehring, E. Llewellin, R. Doust, A. DeMello, and M. Garcia. A. DeMello also helped with measurement of VLF receiver transects. Reviews by R. Hazlett and E. Gallant improved the manuscript greatly. We extend our appreciation to K. Petersen and K. Sullivan for illustration and cartography support and to C. Landowski and K. Pauls for editing the report.

Contents Acknowledgments��iii Abstract��1 Introduction��1 Eruption setting��1 Methods��7 Results��8 Ground cracking��8 Eruption Site��9 Very Low Frequency Measurements��9 Discussion��9 Conclusions��10 References Cited��10 Appendix 1. Ground Crack Data��12 Appendix 2. Nāpau Crater Crack Stations��14 Appendix 3. Clast Density and Vesicularity Data��15 Appendix 4. Very Low Frequency Transect Data��16

Figures 1. 2. 3. 4. 5. 6.

Map showing summit and upper East Rift Zone of Kīlauea and pertinent geological features��2 Maps showing zones of cracking near Pauahi Crater and Kānenuiohamo, Kīlauea, Island of Hawaiʻi��3 Photographs showing new cracks formed during the Father’s Day eruption in 2007, Kīlauea, Island of Hawaiʻi��4 Oblique aerial photographs showing views of fume sources on June 19 and 20, 2007, Kīlauea, Island of Hawaiʻi��5 Maps showing zone of cracking near Kānenuiohamo and location of Father’s Day eruption and fuming cracks on June 19 and 20, 2007, Kīlauea, Island of Hawai‘i��6 Photographs showing June 19, 2007, eruption site views of the west lava pad and the east lava pad, taken on August 10, 2007, Kīlauea, Island of Hawai‘i��7

Conversion Factors U.S. customary units to International System of Units

Multiply

To obtain

Length inch (in.)

2.54

centimeter (cm)

inch (in.)

25.4

millimeter (mm)

foot (ft)

0.3048

meter (m)

mile (mi)

1.609

kilometer (km)

mile, nautical (nmi)

1.852

kilometer (km)

yard (yd)

0.9144

meter (m)

International System of Units to U.S. customary units

Multiply

To obtain

By Length

centimeter (cm)

0.3937

inch (in.)

millimeter (mm)

0.03937

inch (in.)

meter (m)

3.281

foot (ft)

kilometer (km)

0.6214

mile (mi)

kilometer (km)

0.5400

mile, nautical (nmi)

meter (m)

1.094

yard (yd)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows: °F = (1.8 × °C) + 32. Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows: °C = (°F – 32) / 1.8.

Datums Vertical coordinate information is referenced to the World Geodetic System 1984 (WGS 84). Horizontal coordinate information is referenced to the World Geodetic System 1984 (WGS 84). Altitude, as used in this report, refers to distance above the vertical datum.

Abbreviations VLF

Very low frequency

GPS

Global Positioning System

Using Ground Crack and Very Low Frequency Measurements to Map the Location of the June 2007 Father’s Day Dike, Kīlauea By Tim R. Orr, James P. Kauahikaua, and Christina Heliker

Abstract An intrusion into Kīlauea’s upper East Rift Zone during June 17–19, 2007, during the 1983–2018 Pu‘u‘ō‘ō eruption, led to widespread ground cracking and a small (approximately 1,525 cubic meters) eruption on the northeast flank of Kānenuiohamo, a cone about 6 kilometers upslope from Pu‘u‘ō‘ō. Transmitted and induced very low frequency (VLF) magnetic fields were measured with a handheld VLF receiver along transects spanning the dike trace, and zones of ground cracking related to the intrusion were mapped. The locations of crack zones and the VLF receiver measurements suggest that the Father’s Day dike splayed as it approached the surface, dividing into four segments—one between Pauahi Crater and Pu‘uhuluhulu and three en echelon segments near Kānenuiohamo. The dike did not extend appreciably northeastward beyond the eruption site.

Introduction Kīlauea (United States) underwent several changes in 2007. Years of heightened activity, caused by a near-doubling of the magma supply rate to the volcano (Poland and others, 2012), culminated in a magmatic intrusion into Kīlauea’s East Rift Zone that spanned the period June 17–19, 2007. Poland and others (2008) gave an overview of the mid-June 2007 activity, which caused widespread ground cracking in the upper East Rift Zone starting on June 17 and culminated in a short-lived, volumetrically small eruption on the northeast flank of Kānenuiohamo, about 6 kilometers (km) upslope from Pu‘u‘ō‘ō, on June 19 (fig. 1). This activity is informally known as the Father’s Day eruption, since it started on the Father’s Day holiday (United States), and it is categorized as episode 56 of the Pu‘u‘ō‘ō eruption (Orr and others, 2015). The Pu‘u‘ō‘ō eruption lasted in total from 1983 to 2018 (Neal and others, 2019). Here we describe the Father’s Day eruption and discuss a few aspects of the activity not covered elsewhere, including the ground cracking associated with the intrusion and the results of electromagnetic measurements that were made across the trace

of the dike using the very low frequency (VLF) technique (see, for example, McNeill and Labson, 1991). These measurements help us to better understand how the intruding dike splayed as it approached the surface from depth.

Eruption setting From 1997 to 2007, magma traveled from Kīlauea’s summit reservoir through the East Rift Zone to Pu‘u‘ō‘ō, where it erupted from vents on the southwest flank of Pu‘u‘ō‘ō (fig. 1; Heliker and Mattox, 2003; Orr and others, 2015). Lava tube systems carried the lava to the island’s southeast coast. Ephemeral outgassing spatter cones and small lava lakes were also commonly present on Pu‘u‘ō‘ō’s crater floor during this period. Starting in 2003, Global Positioning System (GPS) sensors spanning the volcano’s summit and upper East Rift Zone showed gradual extension, interpreted as pressurization of the summit magma reservoir due to an increase in magma supply (Poland and others, 2012). This manifested as an upsurge in discharge from the vent active at Pu‘u‘ō‘ō at that time. The extent of the pressurization was expressed on May 24, 2007, by two M4+ earthquakes and a brief swarm of smaller events (Wauthier and others, 2013) associated with Kīlauea’s outermost caldera faults. The overall pressurization of the volcano’s magmatic system, however, was unaffected by this seismicity, and extension continued. The pressurized condition of the volcano changed abruptly at 0216 (all times Hawaii Standard Time [HST]) on June 17, 2007, when magma from Kīlauea’s summit began to intrude the volcano’s upper East Rift Zone (fig.1; Poland and others, 2008). Increased seismicity caused nearly continuous ground shaking felt as far away as Volcano, Hawai‘i (fig. 1), about 8 km north of the East Rift Zone. The seismicity was initially centered between Pauahi Crater and Maunaulu but migrated downrift to Makaopuhi Crater over the next two days (fig. 1; Poland and others, 2008). Borehole tiltmeters at the summit of the volcano recorded the onset of rapid deflation at about the same time as the onset of the earthquake swarm, and tiltmeters at Pu‘u‘ō‘ō

2 Using Ground Crack and VLF Measurements to Map the Father’s Day Dike, Kīlauea 155°16' Cra t e r R i m

400

155°12' Driv e

Volcano

155°08' 2200

Private and State land

3800

3600

Kaluapele

320

Map area 2A

Pu‘uhuluhulu

Pauahi Crater Kohala ISLAND OF Koa‘e HAWAI‘I

Mauna Loa

Hilo 30

Makaopuhi Crater 00

Kīlauea

Cra t

e r s Ro ad

Map area

Base from U.S. Geological Survey, The National Map, 10-meter digital elevation data, 2024 Web Mercator Auxillary Sphere World Geodetic System of 1984

2600

19°20'

ystem

Nāpau Crater

Maunaulu

fault s

Mauna Kea

Hualālai

Zon

120

1800

EXPLANATION Pu‘u‘ō‘ō lava flows erupted 1983–2007

0 0

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2 1

Zon

ift st R

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Map area 2B

Rif

Map area 5A

240

3600

Pu‘u‘ō‘ō

Kānenuiohamo

HAWA I‘I V NATIO OLCANOE S NAL P ARK

Father’s Day eruption site

800

19°24'

5 KILOMETERS 3 MILES

Zones of cracking Lava flows erupted 1790–1982 East Rift Zone Koa‛e fault system

Figure 1. Map showing summit and upper East Rift Zone of Kīlauea and pertinent geological features. Kaluapele is the main caldera of Kīlauea. Zones of cracking are related to Father’s Day eruption in June 2007; Pu‘u‘ō‘ō lava flows that erupted 1983–2007 are shown for reference; and lava flows erupted 1790–1982 are also included. Inset, Map of Island of Hawaiʻi showing volcano summits and study area.

began recording deflation a few minutes later (Poland and others, 2008). This was followed by slow subsidence of the floor of Pu‘u‘ō‘ō starting at about 0930 HST on June 17, and spatter cones on the crater floor and on the west and southwest flanks of Pu‘u‘ō‘ō collapsed as they were engulfed by gradually enlarging pits. The crater floor continued to fall over the following days, parts of it dropping about 80

men23-7652_fig01

meters (m) by June 21 (Poland and others, 2008; Orr, 2014). The magma supply to the active tube system was severed as the magma column withdrew, causing the Pu‘u‘ō‘ō eruption to cease. New ground cracks developed in four areas from Pauahi Crater to Kānenuiohamo during the Father’s Day eruption (figs. 1–3), and just after sunrise on June 19, gas emissions

Eruption setting 3 155°13'30"

155°13'00"

155°12'30"

EXPLANATION Zone of cracking near Kānenuiohamo

70, 0.5

19°22'20"

Eruption site and areas of fuming 50, 0.3

Presumed dike trace

Pu‘uhuluhulu n, n

Pauahi Crater 70, 0.4 n

19°22'00"

Cha in

of C

r aters R o ad

70, 2

75, 4 19°21'40"

155°11'15"

155°10'30"

150

300 METERS

500

1,000 FEET

155°9'45"

Hawaii Vo

lcanoes

19°23'00"

Nationa

l Park

Father’s Day eruption site 6

70, 1 19°22'30"

June 19 fuming area

55, 7

65, 11

Kānenuiohamo June 20 fuming area

60, 6 5

19°22'00"

4 Makaopuhi Crater

250

750

500 METERS 1,500 FEET

Figure 2. Maps showing zones of cracking near (A) Pauahi Crater and (B) Kānenuiohamo, Kīlauea, Island of Hawaiʻi. The white arrows indicate length, trend, and transect direction of very low frequency (VLF) transect lines through the zones of cracking at each location.

men23-7652_fig02

Indicate trend of selected cracks; numbers indicate azimuth and amount of opening, in centimeters. Indicate length, trend, and transect direction of VLF line

Using Ground Crack and VLF Measurements to Map the Father’s Day Dike, Kīlauea

D Kānenuiohamo Kānenuiohamo

New

gro

und c

rack

June 20 fuming cracks

Figure 3. Photographs showing new cracks formed during the Father’s Day eruption in 2007, Kīlauea, Island of Hawaiʻi. A, Oblique aerial photograph showing new cracks crossing Chain of Craters Road south of Pauahi Crater on June 17, 2007. Photograph by T. Orr, U.S. Geological Survey. B, Photograph taken showing new cracks cutting lava and tephra surfaces on plain between Maunaulu and Kānenuiohamo on June 18, 2007. Photograph by D. Swanson, U.S. Geological Survey. C, Photograph taken showing new cracks on plain between Maunaulu and Kānenuiohamo, on June 18, 2007, looking along strike. Photograph by M. Poland, U.S. Geological Survey. D, Oblique aerial photograph with a northeast view at new ground cracks on the plain between Maunaulu and Kānenuiohamo on June 21, 2007. Gas emissions from the cracks increased dramatically on June 20, 2007. Photograph by T. Orr, U.S. Geological Survey.

men23-7652_fig03

Eruption setting 5 A

Maunaulu Kānenuiohamo June 19 fuming cracks

June 19 eruption site

B Pu‘u‘ō‘ō June 19 eruption site

Kānenuiohamo June 19 fume source

June 20 fuming cracks

Figure 4. Oblique aerial photographs showing views of fume sources on June 19 and 20, 2007, Kīlauea, Island of Hawaiʻi. A, Oblique aerial photograph looking west (uprift) at fume sources on flank of Kānenuiohamo on June 19, 2007. June 19 eruption site in foreground; more distant area is fume rising from old fissures formed in 1969. Photograph by T. Orr, U.S. Geological Survey. B, Oblique aerial photograph looking east (downrift) at fume sources on and near Kānenuiohamo on June 20, 2007. Gas emissions in foreground were barely evident the previous day (June 19); conversely, robust emissions at the 1969 fissures on Kānenuiohamo on June 19 were nearly nonexistent on June 20. Photograph by C. Heliker, U.S. Geological Survey.

were discovered emanating from two spots in the area of cracking that crossed the flank of Kānenuiohamo (fig. 4). Specifically, whitish gas emissions were streaming profusely from fissures that formed in 1969 on the north flank of the cone, and a robust plume of bluish fume was rising from its heavily forested northeast flank. Fissures had opened at this second location overnight, erupting sparse tephra and two small pads of lava (figs. 5, 6). A third area of barely perceptible fuming was also observed that same morning on the lava plain just east of Kānenuiohamo, but it was no longer apparent a few hours later, as the day warmed and humidity dropped. Fuming from the third area reappeared and increased dramatically in strength overnight, forming a small white plume when seen in the morning on June 20, whereas the June 19 fuming area at the 1969 fissures to the northeast was barely evident (fig. 4B). The June 20 fuming cracks emitted choking gases and were found to be too hot to approach closely, indicating that magma was close to the surface. The Father’s Day eruption was followed by a period of repose at Kīlauea, during which there was no discernable eruptive activity. The Pu‘u‘ō‘ō eruption resumed 12 days later, on July 1, with lava erupting in the bottom of the Pu‘u‘ō‘ō (Orr, 2014). After a period of filling, new fissures opened on the east flank of Pu‘u‘ō‘ō on July 21, marking the start of a new episode of eruptive activity (Orr and others, 2022). The trace of the Father’s Day dike on the forested north flank of Kānenuiohamo became more apparent over the following years (fig. 5), as increased heat flow from the intrusion caused considerable tree die-off while leaving the understory ferns unaffected.

6 Using Ground Crack and VLF Measurements to Map the Father’s Day Dike, Kīlauea 155º10'

19º23'

155º9'

Father’s Day eruption site June 19 fuming area June 20 fuming area

Map area B king

rac

fc eo

Zon

Nāpau Crater Tree die-off

Kānenuiohamo

19º22'

Makaopuhi Crater 0

0.5

1,500

1 KILOMETERS 3,000 FEET

EXPLANATION Areas covered by lava from Father's Day eruption Zone of cracking near Kānenuiohamo

Tree die-off

Eruptive fissure

East lava pad

West lava pad

50 METERS 150 FEET

Figure 5. Maps showing zone of cracking near Kānenuiohamo and location of Father’s Day eruption and fuming cracks on June 19 and 20, 2007, Kīlauea, Island of Hawai‘i. A, Map showing zone of cracking near Kānenuiohamo and location of Father’s Day eruption and fuming cracks. White box indicates location of B, map showing eruptive fissures and areas covered by lava from Father’s Day eruption.

men23-7652_fig05

Methods 7 A

Figure 6. Photographs showing June 19, 2007, eruption site views of the (A) west lava pad and the (B) east lava pad, taken on August 10, 2007, Kīlauea, Island of Hawai‘i. Photographs by T. Orr, U.S. Geological Survey.

Methods The field observations used in this report were conducted on the ground and during helicopter overflights. Activity at Pu‘u‘ō‘ō was also observed by a telemetered webcam on the north rim of the Pu‘u‘ō‘ō cone (Hoblitt and others, 2008). Another telemetered webcam was temporarily deployed on June 20 to the west flank of Maunaulu looking toward Kānenuiohamo. Cracks associated with the Father’s Day eruption were identified on the ground by the exposure of fresh crack surfaces where they cut older pāhoehoe and tephra cover (figs. 3B, C) and sometimes duff where forested. Larger cracks were visible from the air (figs. 3A, D). Crack locations were marked by hand-held GPS devices (horizontal accuracy approximately plus or minus (±) 10 m) during foot traverses across the affected area. The mapped extent of cracking is incomplete, especially where these crack zones border forest, which is heavily vegetated with thick undergrowth in most of this area, and where they abut ʻaʻā flows, which have a

men23-7652_fig06

rubbly carapace that does not preserve small cracks. Crack width and opening direction were measured for a subset of cracks (fig. 2; appendix 1). Crack lengths were not measured during the eruption because of insufficient time and resources during the ongoing volcanic crisis. At later times, it was no longer possible to locate the smaller cracks because they were either covered by soil or had lost their fresh appearance and could not be distinguished from older cracks. In general, the smaller cracks could be traced for up to a few tens of meters before they ended or intersected natural joints in the pāhoehoe surface. The largest cracks could be traced for a few hundred meters, though individual en echelon segments were generally as long as a few tens of meters. In late June 2007, we re-measured five crack stations on the floor of Nāpau Crater (appendix 2) that had been installed shortly after an eruption there in January 1997 (Thornber and others, 2003). The stations were located along a major East Rift Zone crack system related to the 1997 eruption. Each crack station is marked by a set of three or four hardened-steel survey nails arranged in a network that

8 Using Ground Crack and VLF Measurements to Map the Father’s Day Dike, Kīlauea spans the monitored crack. Distances between the nails, marked from the dimple at the center of each nail head, were measured to the nearest millimeter with a fiberglass surveying tape, allowing changes in crack width to be determined. Prior to our measurements in 2007, the crack stations had last been measured in 1999. During our 2007 survey, we found the survey nails to be heavily corroded, but the center of each nail head could still be approximated to within ±1 mm. A south-to-north foot traverse across Nāpau Crater to look for new ground cracks was also conducted. The margins of the lava flows and the extents of the eruptive fissures were mapped on the ground using a hand-held GPS with a horizontal accuracy of ±10 m. Lava and tephra samples were collected by hand, after the eruption ended, from points along the fissures and lava pads (fig. 5). In most locations, tephra (spatter) was collected both from the top surface of the lava flows and from the forest floor beneath them. The density of the basalt erupted (appendix 3) was determined by measuring the weight of spatter and lava clasts in air and water following the approach of Houghton and Wilson (1989). Density was converted to vesicularity using a dense rock equivalent density of 2.75 grams per cubic centimeter (g/cm3) (Lesher and Spera, 2015). Very low frequency electromagnetic energy in the 15–28 kilohertz (kHz) range is transmitted nearly continuously by a global network of high-powered military transmitters, producing a vertical electric field and tangential magnetic field. These components of the VLF wave are affected by local conductivity heterogeneities, such as those caused by shallow intrusive bodies, which can generate an electromagnetic contrast that is orders of magnitude higher in conductivity than the surroundings (Zablocki, 1978; Kauahikaua and others, 1998) that can last for decades (Davis, 2015). For a shallow, narrow conductor, such as a dike, the VLF wave generates an induced magnetic field detectable with a portable VLF receiver, which measures the elliptically polarized sum of the transmitted and induced magnetic fields. This technique has long been used in volcanic settings (for example, Zablocki, 1978; Jackson and others, 1987; Kauahikaua and others, 1996; Davis, 2015), for instance to estimate the location of new dikes (Zablocki, 1978). We used the technique here to locate the trace of the Father’s Day dike.

Results Ground cracking The new ground cracks associated with the Father’s Day eruption were first found where they crossed the Chain of Craters Road southwest of Maunaulu, within Hawaiʻi Volcanoes National Park, midday on June 17 (figs. 1–3). This area is at the eastern end of the Koa‘e fault system, close to where it intersects the East Rift Zone (Duffield, 1975; Swanson and others, 2019). The crack zone was oriented

approximately east–west and was trackable a few hundred meters on either side of the highway. The individual cracks were oriented from about 90° to 115° (roughly parallel to the crack zone) and ranged in width from hairline to 2 centimeters (cm) when first observed, but they continued to grow, and some were found to have widths ranging from 3 to 6 cm the next day (June 18). The main crack crossing the road had the same sense of slip as nearby fault scarps, with a slight north-side-down offset. The road was patched by the National Park Service later in the day on June 18, and the cracks showed no signs of widening after that. The cracks generally stepped left at their tips, although some right steps were also seen. A larger zone of new ground cracks oriented roughly northeast–southwest was found June 18 on the lava plain between Maunaulu and Kānenuiohamo (figs. 1, 2). Later excursions into the area, after the Father’s Day eruption was over, found that some cracks had widened, and additional cracks had formed. The cracks, which ranged in width from hairline to about 10 cm (as measured on June 18), were generally aligned with the trend of Kīlauea’s East Rift Zone (approximately [~] 65°) and were identified by the exposure of fresh crack surfaces and lack of infilling debris and vegetation (figs. 2, 3). On June 18, faint pops and booms were heard when we were in relatively quiet spots sheltered from wind noise. These sounds were probably related to crack development in response to the propagating and ascending dike. The cracks define a ~0.5-km by 3-km zone that extends from near the east base of Maunaulu, across the north flank of Kānenuiohamo, and to the June 19 eruption site (fig. 1). It did not extend as far as the 1972 Maunaulu lava flow, which is 720 meters farther northeast. A poorly developed crack zone oriented roughly northeast–southwest was also found in the area between Pauahi Crater and Pu‘uhuluhulu (figs. 1, 2). Cracks within this zone were oriented at roughly 70° and were generally hairline to a few millimeters across. However, several larger, en echelon cracks at the southwest end of this zone crossed the Maunaulu access road and parking area. One set of cracks even formed a low (~10 cm), north-side-down hump crossing the pavement. The southeast edge of this crack zone borders a large ʻaʻā flow, which does not preserve small cracks because of its rubbly surface, so the shape of the zone as shown in figure 2A probably does not well represent its actual shape. A single crack likely related to the Father’s Day eruption was also found extending across the Chain of Craters Road near Pauahi Crater. The crack opening increased from 4 mm on June 17 to 1 cm by June 21, with north-side down vertical motion that caused a low hump in the paved road. We found no fresh cracks during our traverse of Nāpau Crater, and our re-measurement of the crack stations there found only a few millimeters of movement since the last measurements in 1999. This is within expected error considering the time interval between measurements and the rusted condition of the nails in 2007.

Discussion 9

Eruption Site The Father’s Day eruption site was discovered hours after activity had stopped (cover photo), so direct observations can only narrow its timing to occurring sometime overnight on June 18–19. However, a distinct infrasound signal from the direction of Kānenuiohamo was recorded from 0015 to 0045 HST on June 19, and this is interpreted as the approximate onset and duration of the eruption (Fee and others, 2011). The inferred eruption time was bracketed by an increase in real-time seismic amplitude at a seismic station about 700 m west-northwest that lasted from about 2330 on June 18 to 0200 on June 19. Two small lava pads and a sparse tephra deposit erupted from three east-northeast-trending fissures with azimuths ranging from 64° to 74° (figs. 5,6). The fissures define an overall trend of ~68°. The lava pad to the west is the larger of the two, with a mapped area of about 1,830 square meters (m2) and an estimated average thickness of 0.7 m. This equates to a bulk volume of roughly 1,280 cubic meters (m3). Most of the lava flowed down a gentle slope to the southeast, away from the fissures that fed it. The smaller, east lava pad (fig. 4B) had a mapped area of 490 m2 and an estimated average thickness of 0.5 m, giving it a bulk volume of about 245 m3. The two lava pads were connected by lightly fuming cracks, and numerous other steaming and lightly fuming cracks cut the forest floor nearby, especially to the north and west of the west lava pad. The small total volume (~1,525 m3) of the lava pads suggests a short-lived eruption, which is consistent with the 0.5-hour-long infrasound signal (Fee and others, 2011). Using this duration gives a bulk effusion rate of ~0.8 cubic meters per second (m3/s). The average vesicularity of the spatter and lava (appendix 3) was calculated at 52 percent (range 33–68 percent), which equates to a dense-rock equivalent effusion rate of ~0.4±0.1 m3/s, which is far smaller than the effusion rate of 6–7 m3/s determined for Kīlauea both before and after the Father’s Day eruption (Poland and others, 2012). In addition, the small volume and short duration are unusual compared to other fissure eruptions that occurred during the Pu‘u‘ō‘ō eruption.

Very Low Frequency Measurements The VLF receiver transects we conducted across the Father’s Day dike (appendix 4) help locate its axis where the dike is sufficiently shallow. The depth to which this technique can penetrate is about 100 m (Zablocki, 1978), implying a low-resistivity anomaly shallower than this. It is important to note, though, that the low-resistivity anomaly includes both the dike and a zone of surrounding country rock heated by the dike (Davis, 2015), so the low-resistivity anomaly might be shallower than 100 m while the dike could be slightly deeper. The weeks-long gap between the intrusion and the VLF measurements also would have had little effect on the data, considering that the low-resistivity anomaly associated with a dike can last for decades (Davis, 2015).

Figure 4.5 (appendix 4) shows the tilt and ellipticity profiles for transect 5 (fig. 2B), which crosses the dike trace at the June 20 fuming area west of Kānenuiohamo. The tilt and ellipticity profiles for this transect exhibit the classic shape expected for a transect over a shallow conductor (Zablocki, 1978; Kauahikaua and others, 1996). By comparison, the profiles for transects 1, 2, and 8 (appendix 4) show no such shape, indicating there is no conductive anomaly in that area or it is too deep to be detected (deeper than 100 m). In those profiles that obviously show the presence of a conductive dike (transects 3, 4, 5, and 7; appendix 4), the point where tilt and ellipticity cross the x-axis marks the location of the dike trace on the ground. We can use this, along with the eruption site and the prominent fume sources, to locate and orient the presumed trace of the Father’s Day dike (fig. 2B). The VLF receiver results for transect 6 (appendix 4), which crosses the June 19 fuming area high on the north flank of Kānenuiohamo, are not interpretable, perhaps because the transect extends down the relatively steep slope of the cone of Kānenuiohamo or because the dike is too deep. Instead, we use the alignment between the June 19 fuming area, which transect 6 crosses, and the eruption site (transect 7) to determine that the dike trace in this area has a trend of ~70°. This also matches the trend of the zone of tree die-off that extends between the June 19 fuming area and the eruption site (fig. 5). The dike trace implied by VLF receiver results for transects 4 and 5 trends 65° (fig. 2B). The trace extends toward the lower flank of Kānenuiohamo and is offset about 90 m north from the dike trace between the June 19 fuming area and the eruption site, suggesting that either the dike curves between transects 5 and 6 or that these are en echelon dike segments. The VLF receiver results for transect 3 show a weak indication of the dike, but the results for transect 2 are inconclusive, so we are unable to determine the trend of the dike trace there. Nevertheless, the dike trace probably trends about the same as the dike trace elsewhere, or roughly 65°–70°. Allowing this trend, the location of the dike trace at transect 3 is offset about 85 m north from the dike trace defined by transects 4 and 5. This offset in the dike trace indicates either that the dike curves between transects 3 and 4 or that these are en echelon segments as well.

Discussion The location and orientation of ground cracks between Pauahi Crater and Pu‘uhuluhulu and near Kānenuiohamo define zones oriented approximately northeast–southwest. The northeast end of the crack zone between Pauahi Crater and Pu‘uhuluhulu is offset about 1 km north of the southwest end of the crack zone near Kānenuiohamo. This location suggests that the Father’s Day dike splayed as it approached the surface, perhaps along structural weaknesses, forming separate dike segments, as supported by geodetic modeling (Montgomery-Brown and others, 2010). Although the dike segment between Pauahi Crater and Pu‘uhuluhulu reached a level shallow enough to crack the overlying ground surface, it

10 Using Ground Crack and VLF Measurements to Map the Father’s Day Dike, Kīlauea was still too deep to be detected using the VLF technique. The opening of new cracks in the eastern extension of the Koa‘e fault system could indicate that some magma was diverted there from the East Rift Zone, but it might also be the result of the seaward slip of Kīlauea’s south flank associated with the Father’s Day eruption (Montgomery-Brown and others, 2010). The dike segment near Kānenuiohamo, however, did reach a level shallow enough to be detected using the VLF technique. Although it is possible that the Father’s Day dike near Kānenuiohamo approached the surface as a single curvilinear dike, we believe it more likely that the dike in this area splayed further and approached the surface along at least three en echelon segments as suggested by the VLF receiver results in concert with the locations of the fuming cracks and the eruption site (fig. 2). The seismicity related to the Father’s Day eruption migrated down the East Rift Zone in four pulses (Poland and others, 2008) that may correspond to the four dike segments we identify. If so, the migrating seismicity suggests the dike segments formed sequentially from west to east and culminated with the dike reaching the surface at the point of lowest elevation near the dike’s eastern tip, where lava erupted. Magma rose close enough to the ground surface at the June 20 fuming area on the lava plain west of Kānenuiohamo to expose the top of the magma column to atmospheric pressure, releasing heat and volcanic gases but failing to erupt.

Conclusions The June 17–19, 2007, Father’s Day eruption was the result of the forceful intrusion of magma from Kīlauea’s summit magma reservoir into the volcano’s upper East Rift Zone. The intruding dike splayed as it migrated downrift and ascended, forming at least four separate dike segments that caused cracking of the overlying ground surface. Measurement of very low frequency magnetic fields using a handheld very low frequency receiver, along with the location of outgassing cracks and eruptive fissures, help to define the traces of the eastern three dike segments near Kānenuiohamo. The Father’s Day eruption culminated in a brief (approximately 30 minutes long) eruption early in the morning on June 19, discharging two small pads of lava totaling about 1,525 cubic meters of lava near the eastern end of the dike. Adjusting volume based on the average vesicularity of eruptive products, which is 52 percent, equates to a very low dense-rock equivalent eruption rate of about 0.4 cubic meters per second.

References Cited Davis, P.M., 2015, Geothermal evolution of an intruded dike in the rift zone of Kilauea volcano, Hawaii from VLF and self-potential measurements: Journal of Volcanology and Geothermal Research, v. 302, p. 64–80, https://doi.org/ 10.1016/j.jvolgeores.2015.06.007.

Duffield, W.A., 1975, Structure and origin of the Koae fault system, Kilauea Volcano, Hawaiʻi: U.S. Geological Survey Professional Paper 856, 12 p., https://doi.org/ 10.3133/pp856. Fee, D., Garces, M., Orr, T., and Poland, M., 2011, Infrasound from the 2007 fissure eruptions of Kīlauea Volcano, Hawai‘i: Geophysical Research Letters, v. 38, no. 6, 5 p., https://doi.org/10.1029/2010GL046422. Heliker, C., and Mattox, T.N., 2003, The first two decades of the Pu‘u ‘Ō‘ō–Kupaianaha eruption—Chronology and selected bibliography, chap. 1 of Heliker, C., Swanson, D.A., and Takahashi, T.J., eds., The Pu‘u ‘Ō‘ō–Kupaianaha eruption of Kīlauea Volcano, Hawai‘i—The first 20 years: U.S. Geological Survey Professional Paper 1676, p. 1–27, https://doi.org/10.3133/pp1676. Hoblitt, R.P., Orr, T.R., Castella, F., and Cervelli, P.F., 2008, Remote-controlled pan, tilt, zoom cameras at Kīlauea and Mauna Loa volcanoes, Hawai‘i: U.S. Geological Survey Scientific Investigations Report 2008–5129, 14 p., https://doi.org/10.3133/sir20085129. Houghton, B.F., and Wilson, C.J.N., 1989, A vesicularity index for pyroclastic deposits: Bulletin of Volcanology, v. 51, no. 6, p. 451–462, https://doi.org/10.1007/BF01078811. Jackson, D.B., Hort, M.K., Hon, K., and Kauahikaua, J., 1987, Detection and mapping of active lava tubes using the VLF induction techniques, Kilauea Volcano, Hawaiʻi: Eos, Transactions of the American Geophysical Union, v. 68, no. 44, p. 1543. Kauahikaua, J., Mangan, M., Heliker, C., and Mattox, T., 1996, A quantitative look at the demise of a basaltic vent—The death of Kupaianaha, Kilauea Volcano, Hawai‘i: Bulletin of Volcanology, v. 57, no. 8, p. 641–648, https://doi.org/10.1007/s004450050117. Kauahikaua, J., Cashman, K.V., Mattox, T.N., Heliker, C.C., Hon, K.A., Mangan, M.T., and Thornber, C.R., 1998, Observations on basaltic lava streams in tubes from Kilauea Volcano, island of Hawaii: Journal of Geophysical Research, v. 103, no. B11, p. 27303–27323, https://doi.org/ 10.1029/97JB03576. Lesher, C.E., and Spera, F.J., 2015, Thermodynamic and Transport Properties of Silicate Melts and Magma, chap. 5 of Sigurdsson, H., ed., The encyclopedia of volcanoes (2d ed.): Amsterdam, Elsevier, p. 113–141, https://doi.org/ 10.1016/B978-0-12-385938-9.00005-5. McNeill, J.D., and Labson, V.F., 1991, Geological mapping using VLF radio waves, chap. 7 of Nabighian, M.N., ed., Electromagnetic Methods in Applied Geophysics, Volume 2, Application, Parts A and B: Society of Exploration Geophysicists, p. 521–640, https://doi.org/10.1190/ 1.9781560802686.ch7.

References Cited 11 Montgomery-Brown, E.K., Sinnett, D.K., Poland, M., Segall, P., Orr, T., Zebker, H., and Miklius, A., 2010, Geodetic evidence for en echelon dike emplacement and concurrent slow slip during the June 2007 intrusion and eruption at Kīlauea volcano, Hawaii: Journal of Geophysical Research, v. 115, no. B7, 15 p., https://doi.org/10.1029/ 2009JB006658. Neal, C.A., Brantley, S.R., Antolik, L., Babb, J.L., Burgess, M., Calles, K., Cappos, M., Chang, J.C., Conway, S., Desmither, L., Dotray, P., Elias, T., Fukunaga, P., Fuke, S., Johanson, I.A., Kamibayashi, K., Kauahikaua, J., Lee, R.L., Pekalib, S., Miklius, A., Million, W., Moniz, C.J., Nadeau, P.A., Okubo, P., Parcheta, C., Patrick, M.R., Shiro, B., Swanson, D.A., Tollett, W., Trusdell, F., Younger, E.F., Zoeller, M.H., Montgomery-Brown, E.K., Anderson, K.R., Poland, M.P., Ball, J.L., Bard, J., Coombs, M., Dietterich, H.R., Kern, C., Thelen, W.A., Cervelli, P.F., Orr, T., Houghton, B.F., Gansecki, C., Hazlett, R., Lundgren, P., Diefenbach, A.K., Lerner, A.H., Waite, G., Kelly, P., Clor, L., Werner, C., Mulliken, K., Fisher, G., and Damby, D., 2019, The 2018 rift eruption and summit collapse of Kīlauea Volcano: Science, v. 363, n. 6425, p. 367–374, https://doi.org/10.1126/science.aav7046. Orr, T., 2014, The June-July 2007 collapse and refilling of Puʻu ʻŌʻō Crater, Kīlauea Volcano, Hawaiʻi: U.S. Geological Survey Scientific Investigations Report 2014–5124, 15 p., https://doi.org/10.3133/sir20145124. Orr, T.R., Poland, M.P., Patrick, M.R., Thelen, W.A., Sutton, A.J., Elias, T., Thornber, C.R., Parcheta, C., and Wooten, K.M., 2015, Kīlauea’s 5–9 March 2011 Kamoamoa fissure eruption and its relation to 30+ years of activity from Pu‘u ‘Ō ‘ō, chap. 18 of Carey, R., Poland, M., Cayol, V., Weis, D. (eds.), Hawaiian volcanoes—From source to surface: Hoboken, New Jersey, Wiley, p. 393–420, https://doi.org/ 10.1002/9781118872079.ch18. Orr, T.R., Llewellin, E.W., and Patrick, M.R., 2022, Development, structure, and behavior of a perched lava channel at Kīlauea Volcano, Hawaiʻi, during 2007: Journal of Volcanology and Geothermal Research, v. 430, no. 107637, 18 p., https://doi.org/10.1016/j.jvolgeores.2 022.107637.

Orr, T., 2024, Ground crack, VLF measurement, and sample vesicularity data for the June 2007 Father's Day eruption, Kīlauea Volcano: U.S. Geological Survey data release, https://doi.org/10.5066/P955VWUV. Poland, M., Miklius, A., Orr, T., Sutton, J., Thornber, C., and Wilson, D., 2008, New episodes of volcanism at Kilauea Volcano, Hawaii: Eos (American Geophysical Union Transactions), v. 89, no. 5, p. 37–38, https://doi.org/ 10.1029/2008EO050001. Poland, M.P., Miklius, A., Sutton, A.J., Thornber, C.R., 2012, A mantle-driven surge in magma supply to Kilauea Volcano during 2003-2007: Nature Geoscience, v. 5, no. 4, p. 295–300, https://doi.org/10.1038/ngeo1426. Swanson, D.A., Fiske, R.S., Thornber, C.R., and Poland, M.P., 2019, Dikes in the Koa‘e fault system, and the Koa‘e–east rift zone structural grain at Kīlauea Volcano, Hawai‘i, in PolandM.P., Garcia, M.O., Camp, V.E., and Grunder, A., eds., Field Volcanology—A Tribute to the Distinguished Career of Don Swanson: Geological Society of America Special Paper 538, p. 247–274. https://doi.org/10.1130/ 2018.2538(11) Thornber, C.R., Heliker, C., Sherrod, D.R., Kauahikaua, J.P., Miklius, A., Okubo, P.G., Trusdell, F.A., Budahn, J.R., Ridley, W.I., and Meeker, G.P., 2003, Kilauea east rift zone magmatism—an episode 54 perspective: Journal of Petrology, v. 44, no. 9, p. 1525–1559, https://doi.org/ 10.1093/petrology/egg048. Wauthier, C., Roman, D.C., and Poland, M.P., 2013, Moderate-magnitude earthquakes induced by magma reservoir inflation at Kīlauea Volcano, Hawai‘i. Geophysical Research Letters v. 40,no. 20, p. 5366–5370, https://doi.org/ 10.1002/2013GL058082. Zablocki, C.J., 1978, Applications of the VLF induction method for studying some volcanic processes of Kilauea volcano, Hawaii: Journal of Volcanology and Geothermal Research, v. 3, no. 1-2, p. 155–195, https://doi.org/10.1016/ 0377-0273(78)90008-2.

12 Using Ground Crack and VLF Measurements to Map the Father’s Day Dike, Kīlauea

Appendix 1. Ground Crack Data 155°13'30"

155°13'00"

EXPLANATION

155°12'30"

Zone of cracking near Kānenuiohamo

19°22'20"

Hawai'i Volcanoes national park

Eruption site and areas of fuming n

Crack

Pu‘uhuluhulu

Pauahi Crater 30 19°22'00" 33

32 31

Cha in

of C

r a t e rs R o a d

8 7 9

19°21'40"

155°11'15"

155°10'30"

500

1,000 FEET

150

300 METERS

155°9'45"

Hawai'i

19°23'00"

Volcanoe

s Nationa

l Park

Father’s Day eruption site

23 19°22'30"

June 19 fuming area 21 20 19 16 11 18 17 5 6 14 10 12 13 15 26 27 June 20 Kānenuiohamo 25 24 fuming area 3 2 4 1

750

250

1,500 FEET 500 METERS

Figure 1.1. Maps showing zones of cracking near Pauahi Crater (A) and Kānenuiohamo (B), Kīlauea, Island of Hawaiʻi. The numbered cracks in the zones of cracking on the map correspond to the crack numbers in table 1.1.

Appendix 1. Ground Crack Data 13

Table 1.1.

Identification number, location, trend, width, and opening direction of measured cracks associated with the Father’s Day eruption.

[Data archived in Orr (2024). cm, centimeter; —, not available]

Crack number

Latitude

Longitude

Trend Width (°) (cm)

—

19.373450

−155.178670

—

19.373210

−155.178960

—

19.372660

−155.179070

—

19.373250

−155.180260

0.2

—

19.373760

−155.177980

—

−155.184293

—

19.374310

−155.175360

0.7

—

19.372637

−155.183293

—

19.377280

−155.170940

—

19.372837

−155.181293

1.5

—

19.376420

−155.175030

0.5

145

19.372937

−155.180293

1.5

—

19.370210

−155.177380

1.5

—

19.372737

−155.180293

—

19.370590

−155.177930

1.5

—

19.361538

−155.223293

—

19.371500

−155.178880

—

19.361938

−155.223293

2.5

—

19.371090

−155.185230

—

19.361938

−155.222293

2.5

—

19.371090

−155.185230

—

19.371160

−155.185290

1.5

—

Crack number

Latitude

Longitude

Trend Width (°) (cm)

19.368537

−155.186293

19.368937

−155.186293

19.370037

−155.184293

19.369737

−155.184293

19.369337

−155.184293

19.372237

7 8

Opening direction (°)

19.361938

−155.223293

180

19.361938

−155.223293

180

19.372528

−155.209662

0.5

—

19.362038

−155.224293

—

19.372957

−155.207902

0.3

—

19.361538

−155.223293

1.5

—

19.367518

−155.213224

0.4

—

19.372000

−155.184130

—

19.365281

−155.215117

0.2

—

19.372800

−155.182790

160

19.365077

−155.215842

—

19.372700

−155.181770

125

19.365399

−155.216700

19.372400

−155.181620

—

19.365571

−155.218009

0.7

140

19.372600

−155.180920

150

19.362086

−155.222755

115

0.2

—

19.372900

−155.180380

—

19.361927

−155.222914

—

19.371700

−155.179260

170

19.361661

−155.223073

0.5

—

19.371600

−155.179070

160

19.361395

−155.223126

115

0.1

—

19.370815

−155.226057

0.3

—

19.371500

−155.179010

14 Using Ground Crack and VLF Measurements to Map the Father’s Day Dike, Kīlauea

Appendix 2. Nāpau Crater Crack Stations 155°8'45"

19°22'45"

155°8'30" Station NC1 19.37347, −155.14333 (WGS84)

ava 97 l

flow

Nāpau Crater 19°22'30"

Crack

3 4

Station NC5 19.37497, -155.14017 (WGS84)

19°22'15" 3

2 1

125

250 METERS

400

800 FEET

EXPLANATION Crack station End points of crater traverse

Subsidiary crack

Station NC4 19.37407, −155.14111 (WGS84)

Table 2.1.

Main crack

NC4

NC3

Station NC3 19.37378, −155.14232 (WGS84)

Crack

NC5 NC2 NC1

Station NC2 19.37369, −155.14283 (WGS84)

Crack

EXPLANATION n

Lines and nails of measurement Crack

Crack

Figure 2.1. Maps showing locations of crack monitoring stations and station nail arrangements in Nāpau Crater, Kīlauea, Island of Hawaiʻi. A, Map showing locations of crack stations NC1 to NC5. Lava flows erupted in 1997 outlined in white. B, Crack station maps showing the arrangement of measurement nails across the cracks.

Line lengths between nails for crack stations NC1–NC5 on the dates indicated.

[See figure 2.1 for arrangement of nails. Line lengths are given in centimeters (cm). Dates are shown in MM/DD/YYYY. Data archived in Orr (2024).]

Crack station NC1

NC2

NC3

NC4 NC5

Line

Line Length on Line Length on Line Length on Line Length on Line Length on Line Length on Line Length on 03/13/1997 03/13/1997 04/18/1997 10/17/1997 06/10/1998 12/23/1999 06/27/2007 (cm) (cm) (cm) (cm) (cm) (cm) (cm)

222.0

221.8

222.0

221.8

222.1

221.5

220.9

220.8

220.5

221.0

221.1

221.0

219.0

260.3

260.5

260.1

259.5

218.5

218.4

218.5

218.4

218.6

218.2

216.0

428.7

428.8

428.9

428.6

428.2

427.9

486.7

486.6

486.8

486.7

486.1

485.5

436.7

436.8

436.7

436.3

435.9

458.5

458.4

457.8

457.1

349.7

349.6

347.7

347.8

347.1

346.6

332.9

332.8

332.7

331.2

331.1

330.5

330.2

344.0

343.9

342.4

341.9

341.7

300.8

299.4

299.2

298.8

298.7

166.0

166.2

166.5

167.0

167.5

167.9

220.3

220.5

220.9

221.5

221.9

222.0

222.4

255.5

255.2

254.0

253.5

252.8

251.2

292.8

292.4

292.1

290.9

290.7

289.7

287.9

429.5

429.4

429.2

428.5

428.2

427.6

426.8

340.3

340.0

339.0

338.7

337.9

336.3

Appendix 3. Clast Density and Vesicularity Data 15

Appendix 3. Clast Density and Vesicularity Data Table 3.1. Density and vesicularity data for selected lava and spatter samples from the Father’s Day eruption in the East Rift Zone of Kīlauea, Island of Hawaiʻi. [Data archived in Orr (2024). g/cm3, grams per cubic centimeter; %, percent]

Sample number KE56-2644S

KE56-2645S

KE56-2671S KE56-2672F

KE56-2675S

Clast number

Clast type

Density (g/cm3)

Vesicularity (%)

Spatter

1.35

Spatter

1.42

Spatter

1.62

Spatter

0.93

Spatter

1.34

Spatter

0.99

Spatter

1.08

Spatter

1.08

Flow

1.33

Flow

1.49

Flow

1.48

Flow

0.88

Spatter

1.85

Spatter

1.73

16 Using Ground Crack and VLF Measurements to Map the Father’s Day Dike, Kīlauea

Appendix 4. Very Low Frequency Transect Data

Tilt angle and ellipticity, in percent

Transect 1 6 4

Figure 4.1. Plot showing tilt and ellipticity measurements along transect 1, collected by EM16 VLF receiver on June 27, 2007.

Ellipticity

2 0 −2 −4

Tilt

−6 −8

Table 4.1.

100

150

200

250

300

350

400

450

500

Distance along transect, in meters

550

600

650

700

750

800

EM16 VLF receiver measurements for transect 1, arranged south to north, and collected facing north on June 27, 2007.

[Transect length, 800 meters (m); spacing, 10 m; start point, 19.36267, −155.21484 (World Geodetic System 1984); transect azimuth, 8°. Data archived in Orr (2024). %, percent]

Tilt (%)

Ellipticity (%)

Tilt (%)

Ellipticity (%)

−2

270

−3

540

−2

−3

280

−4

550

−1

−4

−2

290

−5

−1

560

−2

−3

−2

300

−4

−2

570

−1

−3

−4

−2

310

−4

−2

580

−1

−4

−2

320

−3

−2

590

−1

−4

330

−3

−1

600

−1

−4

−1

340

−4

−2

610

−3

−2

350

−4

−1

620

−4

−1

360

−3

−1

630

−1

100

−4

−2

370

−3

640

−1

110

−3

−2

380

−3

650

120

−2

390

−3

660

−1

130

−2

400

−3

670

140

−3

410

−3

−1

680

150

−2

420

−3

−1

690

160

−3

430

−3

700

−1

170

−3

440

−3

−1

710

180

−2

450

−2

−1

720

−1

190

−3

460

−2

−1

730

−1

−2

740

−1

Distance (m)

Tilt (%)

−2

10 20

Ellipticity (%)

Distance (m)

200

−3

470

210

−3

480

−2

−1

750

220

−3

−1

490

−1

760

230

−3

500

−1

770

240

−3

−1

510

−1

780

−1

250

−3

−1

520

−1

−2

790

−1

260

−3

530

−1

−2

800

−1

Appendix 4. Very Low Frequency Transect Data 17

Tilt angle and ellipticity, in percent

Transect 2 8

Figure 4.2. Plot showing tilt and ellipticity measurements along transect 2, collected by EM16 VLF receiver on September 27, 2007.

6 4

Tilt

2 0

Ellipticity

−2 −4

Table 4.2.

100

150

200

250

300

Distance along transect, in meters

350

400

EM16 VLF receiver measurements for transect 2, arranged north to south, and collected facing south on September 27, 2007.

[Transect length, 400 meters (m); spacing, 10 m; start point, 19.36972, −155.18835 (World Geodetic System 1984); transect azimuth, 155°. Data archived in Orr (2024). %, percent]

Distance (m)

Tilt (%)

Distance (m)

Ellipticity (%)

Tilt (%)

Ellipticity (%)

0.5

210

1.5

0.5

220

1.5

0.5

230

0.5

240

250

0.5

260

1.5

0.5

270

280

1.5

0.5

290

3.5

1.5

0.5

300

100

310

110

320

120

0.5

−1

330

130

−1

340

140

−0.5

350

150

−0.5

360

160

370

170

0.5

380

180

0.5

390

190

400

200

men23-7652_figD02

18 Using Ground Crack and VLF Measurements to Map the Father’s Day Dike, Kīlauea

Transect 3 8 6

Tilt

Figure 4.3. Plot showing tilt and ellipticity measurements along transect 3, collected by EM16 VLF receiver on July 10, July 19, and July 31, 2007.

Approximate dike axis

Tilt angle and ellipticity, in percent

2 0 −2

Ellipticity

−4 −6 −8

100

150

200

250

300

350

400

450

Distance along transect, in meters

500

550

600

650

700

Table 4.3. EM16 VLF receiver measurements for transect 3, arranged south to north, and collected facing north on July 10, July 19, and July 31, 2007. [Transect length, 700 meters (m); spacing, 10 m; start point, 19.36619, −155.18340 (World Geodetic System 1984); transect azimuth, 335°. Data archived in Orr (2024). %, percent]

Distance (m)

Tilt (%)

Ellipticity (%)

Distance (m)

Tilt (%)

Ellipticity (%)

Distance (m)

Tilt (%)

Ellipticity (%)

240

−3

480

−1

250

−1

−2

490

−2

−1

−2

260

−2

500

−3

−2

−1

270

−2

510

−2

−1

280

−3

520

−3

−2

−1

290

−3

530

−3

−2

−1

−2

300

−2

540

−4

−2

−1

310

−2

550

−4

−2

320

−2

560

−4

−1

−2

330

−2

570

−4

−1

100

−2

340

−1

580

−5

−1

110

−1

−2

350

590

−4

120

−1

−2

360

−1

600

−4

130

−1

370

610

−5

140

−2

380

620

−5

150

−1

−2

390

630

−5

160

−1

−2

400

640

−4

170

−1

−2

410

650

−4

180

−1

−2

420

660

−4

190

−1

−2

430

670

−4

200

−2

440

680

−4

210

−3

450

690

−3

220

−2

460

700

−3

230

−2

470

−1

men23-7652_figD03

Appendix 4. Very Low Frequency Transect Data 19

Transect 4 Figure 4.4. Plot showing tilt and ellipticity measurements along transect 4, collected by EM16 VLF receiver on July 9, July 10, July 19, and July 30, 2007.

6 4

Tilt

2 0 −2 −4

Approximate dike axis

Tilt angle and ellipticity, in percent

Ellipticity

−6 −8 −10 −12 −14 −16

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

Distance along transect, in meters

Table 4.4. EM16 VLF receiver measurements for transect 4, arranged south to north, and collected facing north on July 9, July 10, July 19, and July 30, 2007. [Transect length, 890 meters (m); spacing, 10 m; start point, 19.36714, −155.18039 (World Geodetic System 1984); transect azimuth, 335°. Data archived in Orr (2024). %, percent]

Distance (m)

Tilt (%)

Ellipticity (%)

Distance (m)

Tilt (%)

Ellipticity (%)

Distance (m)

Tilt (%)

Ellipticity (%)

−4

300

−4

600

−10

−4

310

−4

610

−12

−3

320

−4

620

−12

−4

630

−11

−4

640

−11

−3

330

−4

340

−4

350

−3

650

−4

360

−3

660

−12

−4

370

−2

670

−12

−3

380

−2

680

−11

−3

390

−1

690

−10

100

−3

400

−1

700

−8

110

−3

410

−1

710

−8

−7

120

−3

420

−1

720

130

−4

430

−1

730

−6

140

−4

440

−1

740

−5

150

−4

450

−2

750

−5

160

−4

460

−2

760

−4

770

−4

170

−4

470

180

−4

480

−5

780

−4

−5

790

−4

−10

800

−3

190

−4

490

200

−4

500

210

−4

510

−11

810

220

−4

520

−11

820

−3

230

−4

530

−10

830

−2

240

−4

540

−11

840

−2

250

−4

550

−10

850

−2

−11

860

−2

260

−4

560

270

−4

570

−13

870

−2

−12

880

−2

−13

890

280

−4

580

290

−4

590

−2

20 Using Ground Crack and VLF Measurements to Map the Father’s Day Dike, Kīlauea

Transect 5 18 16 14 12

Tilt

10 8

Tilt angle and ellipticity, in percent

6 4 2 0 −2 −4

Ellipticity

−6 −8

−10 −12 Approximate dike axis

−14 −16 −18 −20 −22 −24

100

150

200

250

300

350

400

450

500

Distance along transect, in meters

550

600

650

700

750

Figure 4.5. Plot showing tilt and ellipticity measurements along transect 5, collected by EM16 VLF receiver on July 5, July 6, July 9, and July 23, 2007.

men23-7652_figD05

800

Appendix 4. Very Low Frequency Transect Data 21 Table 4.5. EM16 VLF receiver measurements for transect 5, arranged south to north, and collected facing north on July 5, July 6, July 9, and July 23, 2007. [Transect length, 760 meters (m); spacing, 10 m; start point, 19.36863, −155.17637 (World Geodetic System 1984); transect azimuth, 335°. Data archived in Orr (2024). %, percent]

Distance (m)

Tilt (%)

Ellipticity (%)

390

−2

400

−2

410

−1

420

−1

430

440

−2

450

−1

460

−2

470

−2

480

−13

−7

100

−2

490

−19

−9

110

−2

500

−21

−8

120

−2

510

−20

−6

130

−2

520

−19

−4

140

−2

530

−18

−1

150

−2

540

−14

160

−3

550

−14

170

−4

560

−16

180

−4

570

−12

190

−4

580

−11

200

−4

590

−9

210

−5

600

−11

220

−4

610

−9

230

−4

620

−8

240

−4

630

−7

250

−4

640

−8

260

−4

650

−8

270

−4

660

−8

280

−4

670

−7

290

−4

680

−6

300

−4

690

−5

310

−3

700

−7

320

−3

710

−5

330

−3

720

−5

340

−3

730

−5

350

−2

740

−3

360

−1

750

−5

370

−2

760

−3

380

−2

Distance (m)

Tilt (%)

Ellipticity (%)

22 Using Ground Crack and VLF Measurements to Map the Father’s Day Dike, Kīlauea

Transect 6 18

Figure 4.6. Plot showing tilt and ellipticity measurements along transect 6, collected by EM16 VLF receiver on August 28, 2007.

16 14

Tilt

Tilt angle and ellipticity, in percent

12 10 8 6 4 2 0 −2 −4

Ellipticity

−6 −8

Table 4.6.

100

150

200

250

300

350

Distance along transect, in meters

400

450

500

EM16 VLF receiver measurements for transect 6, arranged north to south, and collected facing south on August 28, 2007.

[Transect length, 490 meters (m); spacing, 10 m; start point, 19.3784, −155.17008 (World Geodetic System 1984); transect azimuth, 159°. Data archived in Orr (2024). %, percent]

Distance (m)

Tilt (%)

Ellipticity (%)

Distance (m)

Tilt (%)

Ellipticity (%)

1.5

−4.5

250

−2.5

−5

260

12.5

−2

−4.5

270

−2

−4

280

13.5

−1

−4.5

290

1.5

−4.5

300

13.5

1.5

−5

310

2.5

−5

320

14.5

−5

330

13.5

3.5

−5

340

13.5

1.5

100

4.5

−5

350

110

−5

360

120

−5

370

130

−5

380

9.5

140

−5

390

9.5

2.5

150

−5.5

400

160

7.5

−5

410

2.5

170

−5

420

6.5

180

8.5

−5

430

190

−4.5

440

200

−4.5

450

2.5

210

10.5

−4

460

2.5

220

−4

470

2.5

230

11.5

−3.5

480

2.5

240

11.5

−2.5

490

Appendix 4. Very Low Frequency Transect Data 23

Transect 7 Table 4.7. EM16 VLF receiver measurements for transect 7, arranged north to south, and collected facing south on August 10, 2007.

30 28

Tilt

[Transect length, 300 meters (m); spacing 10 m; start point, 19.37827, −155.16310 (World Geodetic System 1984); transect azimuth 155°. Data archived in Orr (2024). %, percent]

24 Dike axis

22 20

Distance (m)

Tilt angle and ellipticity, in percent

Tilt (%)

Ellipticity (%)

300

310

320

−13

330

−14

340

−4

350

−11

−16

360

−14

−11

370

−19

−12

380

−19

−10

−2

390

−17

−8

−4

400

−15

−6

410

−14

−5

420

−11

−3

430

−10

−3

440

−8

−2

450

−6

−1

460

−5

−1

470

−3

−1

480

−3

−1

490

−3

−1

500

−2

−1

510

−2

−1

520

−1

530

−1

540

550

560

570

580

590

600

Ellipticity

−8 −10 −12 −14 −16 −18 −20 −22

100

150

200

250

300

350

400

Distance along transect, in meters

450

500

550

600

Figure 4.7. Plot showing tilt and ellipticity measurements along transect 7, collected by EM16 VLF receiver on August 10, 2007. Thick forest undergrowth prevented measurement of entire transect.

24 Using Ground Crack and VLF Measurements to Map the Father’s Day Dike, Kīlauea

Tilt angle and ellipticity, in percent

Transect 8 6

Figure 4.8. Plot showing tilt and ellipticity measurements along transect 8, collected by EM16 VLF receiver on August 17, 2007.

4 2

Ellipticity

Tilt

−2 −4 −6

100

150

200

250

300

350

400

Distance along transect, in meters

Table 4.8.

EM16 VLF receiver measurements for transect 8, arranged north to south and collected facing south on August 17, 2007.

[Transect length, 400 meters (m); spacing, 10 m; start point, 19.38270, −155.15677 (World Geodetic System 1984); transect azimuth, 155°. Data archived in Orr (2024). %, percent]

Distance (m)

Tilt (%)

Ellipticity (%)

Distance (m)

Tilt (%)

Ellipticity (%)

−1

−1.5

210

−1.5

0.5

−2

220

−1.5

−1

230

−1.5

0.5

−1

1.5

−1

240

−1

250

−1

1.5

−0.5

−1

260

−1.5

−0.5

270

−1.5

−0.5

280

−0.5

−1.5

−0.5

290

−0.5

−1

300

−0.5

1.5

100

−1.5

−0.5

310

−0.5

1.5

110

−1.5

320

−0.5

1.5

−0.5

120

−1.5

−0.5

330

130

−1.5

340

140

−1.5

−0.5

350

−0.5

0.5

150

−1.5

360

−0.5

0.5

160

−1.5

370

−0.5

170

−1.5

−0.5

380

−0.5

0.5

180

−1.5

390

400

0.5

190

−1.5

−0.5

200

−2

−0.5

men23-7652_figD08

Moffett Field Publishing Service Center, California Manuscript approved for publication April 2, 2024 Edited by Kathryn Pauls Layout and design by Kimber Petersen

Orr and others— Using Ground Crack and VLF Measurements to Map the Father’s Day Dike, Kīlauea—SIR 2024–5030

ISSN 2328-0328 (online) https://doi.org/10.3133/sir20245030

Using Ground Crack and Very Low Frequency Measurements to Map the Location of the June 2007 Father’s Day Dike, Kīlauea

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