Cracks in the ground through a Te Aroha maize crop have been posted to Facebook by Waikato Regional Council following the 5.1 magnitude earthquake on Wednesday morning.

"You'll see in one the cracks in his maize crop its as deep as a fencing standard," writes a council spokesperson.

The earthquake occurred near the Kerepehi Fault which is part of the Hauraki rift zone.

The council is asking for other landowners to also submit their photos of any property damaged.

"Our Regional Resilience team would love to see your pictures - and don't forget to let us know the general location."

The Te Aroha farmer demonstrates how the crack in his maize is as deep as the length of a fencing standard. Photo: Supplied.

The M5.1 earthquake occurred at 5:39am on Wednesday January 4, 5km south of Te Aroha.

"We received over 20,000 felt reports from this event which was followed by a moderate aftershock of M3.9 at 11.29am," says a GNS spokesperson.

Cracks have appeared through a maize paddock in Te Aroha following the 5.1M earthquake on December 4. Photo: Supplied.

"Both earthquakes occurred in a similar location to the M3.9 quake on Thursday 29 December, near the Kerepehi Fault which is part of the Hauraki rift zone.

Although in an area of low seismicity – with only six earthquakes larger than M3 occurring between Tauranga and Hamilton in the last ten years – there has been strong shaking in the past with a M4.9 earthquake in Te Aroha in 1972.

What next?

The team at GeoNet say when an earthquake occurs there is always a small possibility that a larger earthquake will follow, "however the most likely scenario is that there will be a number of smaller aftershocks which will taper off with time".

Felt reports from the M5.1 Te Aroha earthquake. Image: GeoNet.

Research jointly undertaken by GNS and the Earthquake Commission in 2016, yielded a newfound understanding of faults in the area between Morrinsville and Te Aroha.

The paper demonstrated that in the past earthquakes in the range of M6.3–7.0 have occurred and 'should be considered with respect to future hazard and risk”.

The area's reputation as seismically inactive belies its ability to put nearby population centres at risk, the paper said.

Predicated against the Mercalli Intensity Scale (MMI), a scale which measures the effect of an earthquake rather than its force, the paper finds that Auckland, Hamilton and Tauranga may be at risk.

'The three large population centres of northern North Island–Auckland, Hamilton and Tauranga – may experience MMI 6–7 shaking as the maximum impact associated with rupture of the nearest segments of the fault.”

Modern LiDAR (light detection and ranging) mapping of the region demonstrated 'a far more complex pattern” of historic fault remnants, those which bear a similar surface pattern in terms of 'density and complexity to that described from the Taupo Rift”, than initially thought.

Dr Lauren Vinnell of Massey University's Joint Centre for Disaster Research reminded those in the area, which in the past has avoided earthquakes, to prepare accordingly.

'Earthquakes can definitely be unsettling for people who haven't felt many - everywhere in NZ can get earthquakes strong enough to damage and cause injury, so this is a good reminder to do some preparation.

'For example, you can store some water, secure tall furniture to the wall, move heavy items lower down on shelves, and make an emergency plan with your household.”

Vinnell said that, by-in-large, Kiwis are heeding messaging to disregard antiquated advice to shelter under door frames.

'I'd actively discourage going to a doorway as you might get injured trying to get there ... The current recommended action is to drop, cover, and hold. New Zealanders are learning this message pretty well, but it's important to understand the why of these actions, so you can use them in different contexts.”

Keeping an eye on earthquakes, volcanoes and news on the go.

No matter where the holidays take you, the GeoNet App will keep you updated on earthquakes, volcanoes and geohazard news.

"Our app gives details of all earthquakes located in and around New Zealand within a few minutes of their occurrence,?" says a GeoNet spokesperson.

"You can set up notifications of earthquakes close to your current location using your phone's GPS, or you can set up alerts for multiple locations and earthquake intensities around the country."

The GeoNet app also provides latest news and keeps app users updated on volcanic activity.

"And for our technical users you can view peak ground accelerations (PGA) and velocities (PGV) recorded by our seismograph network on a map."

Download the GeoNet app on your Android and iOS devices:

Google Play for Android

The App Store for Apple

GNS Science's National Geohazards Monitoring Centre (NGMC) remains staffed and monitoring geological hazards 24/7 throughout the holiday period. They are supported by teams of scientists and experts who are on-call should any geological events occur.

Going to the beach?

If you are off to the beach this summer you can now easily see if your favourite holiday spot is in a tsunami evacuation zone thanks to the National Emergency Management Agency (NEMA). Just put in your address or click a spot on the map and you will see if you are in tsunami evacuation zone, and what to do if there is a tsunami. It also links you to the local Civil Defence group for more tsunami information. Click here to check it out.

Tsunami evacuation zones for Waitārere Beach. Image: Supplied.

They also have a handy Get Summer Ready page with all the info you need to get summer ready.

Staying at home?

If you have a list of jobs to get done around the house this summer, now is a great time to check out Toka Tū Ake EQC's website for information on how to get your home, apartment, or rental prepared for a natural disaster.

We can't prevent natural hazards, but we can, and should, be prepared for them.

Earthquakes can occur anywhere in New Zealand at any time. Drop, Cover, and Hold during a large earthquake. If it is Long and Strong, Get Gone! If you are near the coast or a lake and if you feel a Long or Strong earthquake, or receive an emergency mobile alert for a tsunami, Get Gone to higher ground, or as far inland as possible immediately.

During volcanic activity, follow official advice provided by your local Civil Defence Emergency Management Group.

Want to get prepared?

For information on preparing for earthquakes or responding to volcanic activity, there are guidelines from the National Emergency Management Agency's Get Ready website.

Prepare your home. Protect your whānau.

There's a lot we can do to make our homes safer and stronger for natural disasters. Toka Tū Ake EQC's website has key steps to get you started.

All right? / Not All Right?

We all need a bit of support from time-to-time, and if you or someone you know is struggling, there is  free help available. Free call or text 1737 any time, 24 hours a day. You can also call Lifeline on 0800 543354 or text HELP to 4357.

Additional reporting Jonah Franke-Bowell/Stuff