Hawai'i Volcano Blog

Volcano Watch: Tech Talk Part 1: Electronic ‘Doctor’ Tracks Health of Monitoring Stations

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A volcano-monitoring station “health monitor” developed by CJ Moniz at the Hawaiian Volcano Observatory (HVO). It consists of three programmable circuit boards (bottom row), voltage sensors (top row), a current sensor (top right corner), and a custom-made voltage sensor for a 48VDC system (tan circuit board on the bottom right). This unit is deployed in a watertight box to help the electronics withstand harsh environmental conditions. USGS photo.

As part of Volcano Awareness Month earlier this year, Volcano Watch featured five articles focused on different roles at the USGS Hawaiian Volcano Observatory (HVO). These articles described the roles of geodesist, Scientist-in-Charge, gas geochemist, seismologist, and geologist. This month, we continue that series, focusing on the role of technician.

Technicians at HVO engineer and maintain the network of stations that monitor the active volcanoes in the state of Hawai‘i. In the lab, HVO technicians work with scientists to develop technologies and to engineer components needed for volcano monitoring. In the field, technicians install new stations and maintain existing stations, ensuring that essential volcano-monitoring data are collected and transmitted back to HVO for scientific analysis.

HVO technicians utilize a diverse range of tools, instruments, power, and communication systems. HVO technicians are also masterful “MacGyvers.” For example, during Kīlauea’s 2018 eruption, one HVO technician was able to rapidly perform an emergency electronic repair of seismic data acquisition systems that allowed the seismic stations to continue to gather and transmit valuable data back to HVO at a time of critical need.

This week’s article focuses on HVO technician CJ Moniz and his development of a tool that measures and tracks the health of volcano-monitoring stations.


Have you ever opened the door to a doctor’s waiting room to see all the people waiting ahead of you? Sniffing, coughing, needing a few stitches, or a vaccine, you can’t help but realize how important it is to stay healthy (especially now). Sometimes it feels that way for CJ, a physical science technician at HVO who cares for his electronic “patients” — volcano-monitoring stations — all over the Island of Hawai‘i. Through technology and ingenuity, CJ keeps ­­­HVO’s monitoring stations happy and healthy, minimizing the time his patients spend in the waiting room.

HVO has more than 240 stations in its monitoring networks on the Big Island. The stations measure and record earthquakes, ground movement, volcanic gases, sound waves, lava advancement, magma volume below ground, and visual changes in eruptive activity. These stations continuously transmit data to HVO, where they are processed by specialized computer programs and analyzed by scientists.

Since these instruments provide HVO with continuous information on the vital systems of our volcanoes, it’s important that these stations operate at optimal levels and without disruptions. But things can go wrong. Batteries can fail. Instruments can quit working. Radios can stop transmitting. All of which and more can result in data not being collected or transmitted to HVO.

To minimize data disruptions, CJ developed a station “health monitor.” These monitors are installed at major monitoring network hubs. The monitors transmit data to HVO so that every morning CJ can see how the stations are functioning and track their performance over time. The monitors provide information on station voltage, current, data transmission rates, and some even provide weather/atmospheric data.


These monitors are made at HVO, using hobby boards, single board computers (SBC), and bits of pieces of electronics so they aren’t expensive. These monitors were also carefully designed to draw minimal power. The design has been modified and fine-tuned over the five years that they have been in use, to make them more efficient and effective.

Because of this technology, CJ and the other HVO technical staff can see trends and take appropriate actions (remotely sometimes) to “cure” a “sick” station. As one example, CJ’s monitoring system recently indicated that a station was suffering from a decline in voltage, probably due to the wet weather our island has been experiencing. Based on his diagnosis, the technical team at HVO was able to visit the site and change out the battery system before the station went offline. This state of health monitoring system, combined with proactive maintenance, ensured that there was no loss of data and no interruption of service from this station.

This strategic approach to network health monitoring and proactive station maintenance, made possible by the know-how, hard work, and creativity of CJ and other HVO technicians, keeps HVO’s data streams healthy and strong in order to provide scientists with the most up to date and complete information possible.

Volcano Activity Updates


Kīlauea Volcano is not erupting. Its USGS Volcano Alert level remains at NORMAL. Kīlauea updates are issued monthly.

Kīlauea monitoring data for the past month show variable but typical rates of seismicity and ground deformation, low rates of sulfur dioxide emissions, and only minor geologic changes since the end of eruptive activity in September 2018. The water lake at the bottom of Halema‘uma‘u continues to slowly expand and deepen. For the most current information on the lake, go online.

Mauna Loa is not erupting and remains at Volcano Alert Level ADVISORY. This alert level does not mean that an eruption is imminent or that progression to an eruption from the current level of unrest is certain. Mauna Loa updates are issued weekly.

This past week, about 153 small-magnitude earthquakes were recorded beneath the upper-elevations of Mauna Loa, Most of these occurred at shallow depths of less than five miles. Global Positioning System (GPS) measurements show long-term slowly increasing summit inflation consistent with magma supply to the volcano’s shallow storage system. Gas concentrations and fumarole temperatures as measured at both Sulphur Cone and the summit remain stable. Webcams show no changes to the landscape. For more information on the current monitoring of Mauna Loa Volcano, go online.

There were four events with three or more felt reports in the Hawaiian islands during the past week: a magnitude-1.8 earthquake five miles ENE of Pāhala at a 19-mile depth on June 20 at 4:06 p.m. HST; a magnitude-2.1 earthquake four miles E of Pāhala at a 21-mile depth on June 20 at 04 p.m. HST; a magnitude-3.6 earthquake four miles NE of Pāhala at a 20-mile depth on June 20 at 03:49 p.m. HST; and a magnitude-3.4 earthquake three miles NE of Pāhala at a 21-mile depth on June 18 at 3:37 p.m. HST.

HVO continues to closely monitor both Kīlauea and Mauna Loa for any signs of increased activity. Email questions to [email protected].

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