A Tale of Two Earthquakes

Two earthquakes of the same magnitude strike our island a month apart. Two events that are quite interesting to us at the observatory. Both about the same magnitude, both occurring deep in the island, one was far more forceful at the telescopes causing some minor damage, the second caused no damage that we have found despite a thorough inspection.

Mauna Kea seen at dawn from Mauna Loa
Mauna Kea seen at dawn from Mauna Loa

Any strong earthquake is a concern for the telescopes. We need to know immediately just how strong the quake was, how much potential for damage occurred.

The telescopes are precision instruments with many delicate parts. On the other hand earthquakes are common on this volcanic island and we have learned how to deal with the shaking.

When attempting to measure the possible damage to the telescope it is not earthquake magnitude that is interesting. Rather we want to know the peak ground accelerations that occur at the summit facility. The actual forces that could potentially cause damage. These are measured by means of a logging accelerometer mounted in the basement of the observatory.

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Keep it Running

Some equipment around the observatory is thirty or more years old. As you would expect, keeping it running can be a challenge.

A redesigned small signal PCB for an Inland Motor FCU-100-30 amplifier power supply
A redesigned small signal PCB for an Inland Motor FCU-100-30 amplifier power supply

There are two ways of dealing with this old equipment… Replacing it with something new is the preferred way. When it becomes difficult to locate spare parts, when it breaks down too often, just replace it with new gear. For much of the equipment this is the usual answer and is often a major part of the job.

Some equipment is not so easily replaced. When replacement would require wholesale redesign of a system it becomes more of a challenge. Sometimes the only choice is to keep that old gear running.

This is the case with our servo amplifiers. Twelve amplifiers supply the power that drives the telescope, one amplifier for each motor. Eight amplifiers and motors drive azimuth, four drive elevation. Three hundred and seventy tons moved by twelve relatively small DC motors. While much of the telescope control system was recently replaced, it was decided to keep the old servo amplifiers.

You might notice that these servo amplifiers are just a wee bit critical.

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Winter on The Mauna

The warnings sound pretty bad, high winds, high surf, snow for the summit. The county has closed all beach parks, the state has closed most of the parks in anticipation of the bad weather.

Keck 1 dome with a liberal coating of ice from freezing fog
Keck 1 dome with a liberal coating of ice from freezing fog

The summit of Mauna Kea is currently seeing sustained winds of over 80mph, with gusts well over 100mph. Yes, the summit is closed to the public and observing has been cancelled at Keck.

Meanwhile it is eerily still at the house, almost no breeze and quite pleasant. Waiting for the storm to arrive.

I will not be going up anytime soon. Taking a little time off to spend with some family that will be on island, hopefully landing right about now.

I was up a couple days ago… It was impressive then, 40mph winds and everything covered with inches of ice. I braved the biting wind to wander about and take a few photos. Very cold, and very beautiful.

Kepler Goes Silent

This last week we said goodbye to a truly pioneering space telescope. The Kepler mission was designed to find exoplanets, planets that orbit around other stars. The mission succeeded beyond everyone’s expectations.

Kepler
Artist’s rendition of the Kepler Spacecraft in orbit around the Sun peering at a distant solar system, press release image from the NASA Kepler website
This little space telescope monitored over 500,000 stars during it’s mission, watching for the minuscule dip in brightness as a panet passed in front of the star. For nine years Kepler stared at those thousands of stars, during that time it discovered over 2,600 exoplanets. Along with the planets came a long list of other discoveries such as binary stars, variable stars, and novae.

After nine productive years this engine of discovery has come to an end. With the spacecraft out of fuel NASA flight engineers sent the last commands, shutting the spacecraft down.

The Keck Observatory and the Kepler Spacecraft had a great partnership. It was not possible to confirm most Kepler’s possible exoplanets using only data from the spacecraft. A large telescope using a high resolution spectrograph, like HIRES on Keck 1, would allow astronomers to not only confirm Kepler’s discovery, but to learn more about each exoplanet.

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A Very Unstable Day

The ground beneath us is one constant in life you just expect to never change. Solid and unyielding, we build our lives upon the firm foundations of the Earth. When this constant betrays us it is truly disconcerting. The world loses some of its comforting stability.

Last Friday was a day when our islands were reminded of the instability of our world in a rather abrupt fashion.

USGS Earthquake Map for 1May2018
USGS Earthquake Map for May 6, 2018
It was clear weeks ago that the volcano was restless. volcanophiles like myself found ourselves checking the reports and charts daily. The deformation graphs are a good indication of what is going on inside the volcano.

The tiltmeters indicated that pressure in the caldera and Puʻu Oʻo had been building steadily. At the same time the activity in the 61g lava had been waning. Where was the magma going?

While speculation was rife, no one really knew what was coming. Three decades of eruptions from Puʻu Oʻo has become somewhat routine. People forget that Kilauea can be, and usually is much more unpredictable. That destruction can appear anywhere on her flanks.

USGS Leilani Eruption, 5 May, 2018
Lava emerges from a fissure in the Leilani Estates subdivision on May 5th, 2018, photo from the USGS
The first lava surfaced Thursday afternoon in the neighborhood of Leilani Estates. The observatory staff had gathered to celebrate a pau hana that afternoon, an early Cinco De Mayo celebration with Mexican food. Many of us ate our tacos and quesadillas in the conference room, where the large screen was showing drone video of the first fissures.

We worried about the homes in the neighborhood and the people we knew who lived in the area. We compared notes, recalling who lived exactly where, fearing the lava flows would quickly spread. This was looking like a worst case scenario, a repeat of 1955 with more people and homes in the way.

Despite the outbreaks of lava in the rift zone the previous afternoon, we expected a routine Friday atop Mauna Kea. I had a list of tasks to complete… Inspect the K1 azimuth wrap, drill some anchor points to allow installation of the new ice monitor receiver on the roof, look for some spare parts for an encoder.

It should be an easy day on the summit… It was not.

Friday became a day I will remember for a long time to come.

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